Difference between revisions of "User Changes Trunk"

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== About this page==
 
== About this page==
  
−
Below you can find a list of intentional changes since the [[User_Changes_2.4.4|previous release]] that can change the behaviour of previously working code, along with why these changes were performed and how you can adapt your code if you are affected by them. The list of new features can be found [[FPC_New_Features_Trunk|here]].
+
Listed below are intentional changes made to the FPC compiler (trunk) since the [[User_Changes_3.2.2|previous release]] that may break existing code. The list includes reasons why these changes have been implemented, and suggestions for how you might adapt your code if you find that previously working code has been adversely affected by these recent changes.  
 +
 
 +
The list of new features that do not break existing code can be found [[FPC_New_Features_Trunk|here]].
 +
 
 +
Please add revision numbers to the entries from now on. This facilitates moving merged items to the user changes of a release.
  
 
== All systems ==
 
== All systems ==
  
−
===Usage Changes===
+
=== Language Changes ===
−
 
 
−
==== Static keyword is enabled without switches and directives ====
 
−
* '''Old behaviour''': Using the ''static'' keyword required passing the ''-St'' switch to the compiler or using the '' {$STATIC on}'' directive.
 
−
* '''New behaviour''': The ''static'' keyword is now always enabled.
 
−
* '''Effect''': The ''-St'' switch has been deprecated and the ''{$STATIC on/off}'' directive no longer exists.
 
−
* '''Reason''': The compiler can now always correctly determine whether ''static'' is used as a modifier or as a field name, and recent Delphi versions support ''static'' class methods without any special switches.
 
−
* '''Remedy''': Adjust your build scripts and source code by removing all ''-St'' parameters and and ''{$STATIC on/off}'' statements.
 
  
−
==== The POINTERARITHMETICS mode switch has been replaced with the POINTERMATH directive ====
+
==== Precedence of the IS operator changed ====
−
* '''Old behaviour''': Pointer arithmetic was enabled in FPC/OBJFPC and partly (except using pointer as array) in DELPHI modes by default. To enable pointer arithmetic in other modes, {$MODESWITCH POINTERARITHMETICS} had to be enabled.
+
* '''Old behaviour''': The IS operator had the same precedence as the multiplication, division etc. operators.
−
* '''New behaviour''': Pointer arithmetic is enabled in FPC/OBJFPC modes and disabled in DELPHI mode. The new directive {$POINTERMATH ON/OFF} can be used to toggle pointer arithmetic support. Types declared while {$POINTERMATH ON} is in effect also support pointer arithmetic.
+
* '''New behaviour''': The IS operator has the same precedence as the comparison operators.
−
* '''Effect''': {$MODESWITCH POINTERARITHMETICS} is no longer exists. Pointer arithmetic is disabled by default in DELPHI mode.
+
* '''Reason''': Bug, see [https://bugs.freepascal.org/view.php?id=35909].
−
* '''Reason''': Delphi compatibility.
+
* '''Remedy''': Add parenthesis where needed.
−
* '''Remedy''': Check your source code for {$MODESWITCH POINTERARITHMETICS} directives and replace them with {$POINTERMATH ON}. If your source files are using DELPHI mode and you use pointer arithmetic then add the {$POINTERMATH ON} directive to your source files.
 
  
−
====Compiler no longer searches for utilities in the current directory====
+
==== Visibilities of members of generic specializations ====
−
* '''Old behaviour''': The compiler first searched the current directory for external utilities (the assembler, linker, resource compiler, ...) before other locations (directory containing the compiler binary, directories in the PATH).
+
* '''Old behaviour''': When a generic is specialized then visibility checks are handled as if the generic was declared in the current unit.
−
* '''New behaviour''': The compiler will no longer search the current directory for external utilities, except when explicitly instructed to do so (via ''-FD.'', or if the current directory is in the PATH)
+
* '''New behaviour''': When a generic is specialized then visibility checks are handled according to where the generic is declared.
−
* '''Reason''': The old behaviour was a security issue, since a rogue binary with the same name as a helper utility in the current directory (e.g., ''/tmp'' on a Unix-based system) could compromise your account.
+
* '''Reason''': Delphi-compatibility, but also a bug in how visibilities are supposed to work.
−
* '''Remedy''': Put external utilities in a fixed location on your system and add that directory to the path. Note that on most systems this is the case by default, and no configuration changes will be required.
+
* '''Remedy''': Rework your code to adhere to the new restrictions.
  
−
=== Language changes ===
+
=== Implementation Changes ===
  
−
==== Passing derived classes to var- and out-parameters====
+
==== Disabled default support for automatic conversions of regular arrays to dynamic arrays ====
 +
* '''Old behaviour''': In FPC and ObjFPC modes, by default the compiler could automatically convert a regular array to a dynamic array.
 +
* '''New behaviour''': By default, the compiler no longer automatically converts regular arrays to dynamic arrays in any syntax mode.
 +
* '''Reason''': When passing a dynamic array by value, modifications to its contents by the callee are also visible on the caller side. However, if an array is implicitly converted to a dynamic array, the result is a temporary value and hence changes are lost. This issue came up when adding [https://bugs.freepascal.org/view.php?id=35580 TStream.Read() overloads].
 +
* '''Remedy''': Either change the code so it no longer assigns regular arrays to dynamic arrays, or add ''{$modeswitch arraytodynarray}''
 +
* '''Example''': this program demonstrates the issue that appeared with the TStream.Read() overloads that were added (originally, only the the version with the untyped variable existed)
  
−
* '''Old behaviour''': If a routine was declared with a var- or out-parameter of a certain class type, the compiler also allowed passing derived classes to this parameter.
+
<syntaxhighlight lang="pascal">
−
* '''New behaviour''': The compile-time type of a class passed to a routine now has to match the declared parameter type exactly in case of var- and out-parameters.
 
−
* '''Example''':
 
−
<delphi>
 
 
{$mode objfpc}
 
{$mode objfpc}
−
 
 
type
 
type
−
   ta = class
+
   tdynarray = array of byte;
−
  end;
 
  
−
   tb = class(ta)
+
procedure test(var arr); overload;
−
  end;
+
begin
 +
   pbyte(arr)[0]:=1;
 +
end;
  
−
var
+
procedure test(arr: tdynarray); overload;
−
  b: tb;
 
−
 
 
−
procedure test(var a: ta);
 
 
begin
 
begin
−
   a:=ta.create;
+
   test[0]:=1;
−
  // now b contains an instance of type "ta"
 
 
end;
 
end;
  
 +
var
 +
  regulararray: array[1..1] of byte;
 
begin
 
begin
−
   b:=nil;
+
   regulararray[1]:=0;
−
   test(b);
+
   test(arr);
 +
  writeln(arr[0]); // writes 0, because it calls test(tdynarr)
 
end.
 
end.
−
</delphi>
+
</syntaxhighlight>
−
The compiler used to accept the above program, but now it will give an error at the call to ''test''.
+
* '''svn''': 42118
−
* '''Reason''': As the example above demonstrates, allowing this behaviour circumvents the language's type checking. This change is also Delphi-compatible.
 
−
* '''Remedy''': Rewrite the affected code so it that all var/out-parameters and the class types passed to them match exactly. There are ways to circumvent the type checking at the caller side by using explicit type conversions, but using such hacks is strongly discouraged since the resulting code is not type-safe.
 
  
−
====''Array of const'' parameters and cdecl routines====
+
==== Directive clause ''[…]'' no longer useable with modeswitch ''PrefixedAttributes'' ====
 +
* '''Old behaviour''': A function/procedure/method or procedure/method variable type could be followed by a directive clause in square brackets (''[…]'') that contains the directives for the routine or type (e.g. calling convention).
 +
* '''New behaviour''': If the modeswitch ''PrefixedAttributes'' is enabled (which is the default in modes ''Delphi'' and ''DelphiUnicode'') the directive clause in square brackets is no longer allowed.
 +
* '''Reason''': As custom attributes are bound to a type/property in a way that looks ambiguous to a directive clause and this ambiguity is not easily solved in the parser it is better to disable this feature.
 +
* '''Remedy''':
 +
** don't set (in non-''Delphi'' modes) or disable modeswitch ''PrefixedAttributes'' (in ''Delphi'' modes) if you don't use attributes (''{$modeswitch PrefixedAttributes-}'')
 +
** rework your directive clause:
 +
<syntaxhighlight lang="pascal">
 +
// this
 +
procedure Test; cdecl; [public,alias:'foo']
 +
begin
 +
end;
  
−
* '''Old behaviour''': It was possible to have non-external ''cdecl'' routines with an ''array of const'' parameter.
+
// becomes this
−
* '''New behaviour''': ''Cdecl'' routines with an ''array of const'' parameter now always must be external.
+
procedure Test; cdecl; public; alias:'foo';
−
* '''Reason''': In FPC, adding an ''array of const'' parameter to a ''cdecl'' routine has the same effect as adding the ''varargs'' modifier. It means that the routine takes a C-style variable number of arguments. There is however no way in (Free) Pascal to access these arguments on the callee side. This change means that both ''varargs'' and ''array of const'' are treated consistently, since ''varargs'' routines already had to be external.
 
−
* '''Remedy''': Remove the ''cdecl'' specifier and use a Pascal-style ''array of const'', or implement the routine in C and add ''external'' to the Pascal declaration.
 
−
 
 
−
==== String constants longer than 255 chars ====
 
−
* '''Old behaviour''': String constants longer than 255 chars were silently cut off after 255 chars under certain circumstances.
 
−
* '''New behaviour''': String constants longer than 255 chars cause an error in ''{$H-)'' state, and in ''{$H+}'' state an ansistring constant is generated.
 
−
* '''Reason''': Silently truncating string constants is undesired behaviour.
 
−
* '''Remedy''': Manually truncate string constants longer than 255 chars or use ''{$H+}''.
 
−
 
 
−
====Short/Ansistring typed constants containing widechars/unicodechars====
 
−
* '''Old behaviour''': The compiler accepted ''shortstring'' and ''ansistring'' typed constant declarations to which ''widestring'' or ''unicodestring'' constants were assigned (string constants containing widechars/unicodechars, i.e.,  character constants of the form ''#$xxx'', ''#$xxxx'' or ''#yyy'' with ''yyy > 255'', or character literals outside the ASCII range while the code page is different from the default one).
 
−
* '''New behaviour''': The compiler will reject such declarations now.
 
−
* '''Example''':
 
−
<delphi>
 
−
{$codepage utf8}
 
−
 
 
−
{ this example assumes that the source file has been saved using utf-8 encoding }
 
−
 
 
−
const
 
−
  s1: shortstring = 'éà';
 
−
  s2: ansistring = #$094#$06D;
 
−
  s3: ansistring = #267#543;
 
 
begin
 
begin
−
end.
+
end;
−
</delphi>
+
</syntaxhighlight>
−
All three declarations above used to be accepted, but are now rejected. The reasons are that
+
* '''svn''': 42402
−
* the string assigned to ''s1'' has been encoded as an utf-8 string and contains non-ASCII characters
 
−
* the string assigned to ''s2'' contains hexadecimal character constants declared with more than 2 digits
 
−
* the string assigned to ''s3'' contains character values > 255
 
−
In all cases, the practical upshot is that the string on the right hand side of the assignment will be treated as a wide/unicodestring constant at compile time.
 
−
* '''Reason''': The encoding of shortstrings and ansistrings is always the system (ansi) encoding at run time. This system encoding can be different every time the program is run, and hence cannot be determined at compile time. It is therefore not possible for the compiler to convert a wide/unicodestring constant to an ansi/shortstring at compile time. See also [http://bugs.freepascal.org/view.php?id=16219 bug report 16219].
 
−
* '''Remedy''': If you require the string's characters to contain particular ordinal values, declare the string constant as a sequence of byte-sized values (i.e., values <= 255, and in case of hexadecimal notation only use two digits), or do not use any ''{$codepage xxx}'' directive nor [http://unicode.org/faq/utf_bom.html#bom1 an UTF BOM]. In all other cases, declare the typed constant as a ''widestring'' or ''unicodestring''.
 
  
−
====Implicit "result" variable in MacPas mode====
+
==== Type information contains reference to attribute table ====
−
* '''Old behaviour''': In MacPas mode, all functions could automatically access the function result via the implicitly defined ''result'' alias (like in Delphi and ObjFPC mode).
+
* '''Old behavior''': The first field of the data represented by ''TTypeData'' is whatever the sub branch of the case statement for the type contains.
−
* '''New behaviour''': The ''result'' alias is no longer defined by default in MacPas mode.
+
* '''New behavior''': The first field of the data represented by ''TTypeData'' is a reference to the custom attributes that are attributed to the type, only then the type specific fields follow.
−
* '''Reason''': It is not available in Mac Pascal compilers either, and can mask other identifiers thereby changing the behaviour of code.
+
* '''Reason''': Any type can have attributes, so it make sense to provide this is a common location instead of having to parse the different types.
−
* '''Remedy''': You can reenable the ''result'' alias by adding ''{$modeswitch result}'' to your program code (''after'' any ''{$mode macpas}'' statements), or by using the ''-Mresult'' command line option (''after'' any ''-Mmacpas'' parameter, and provided there are no ''{$mode xxx}'' directives in the source).
+
* '''Remedy''':
 +
** If you use the records provided by the ''TypInfo'' unit no changes ''should'' be necessary (same for the ''Rtti'' unit).
 +
** If you directly access the binary data you need handle an additional ''Pointer'' field at the beginning of the ''TTypeData'' area and possibly correct the alignment for platforms that have strict alignment requirements (e.g. ARM or M68k).
 +
* '''svn''': 42375
 +
==== Explicit values for enumeration types are limited to low(longint) ... high(longint) ====
 +
* '''Old behavior''': The compiler accepted every integer value as explicit enumeration value. The value was silently reduced to the longint range if it fell outside of that range
 +
* '''New behavior''': The compiler throws an error (FPC mode) or a warning (Delphi mode) if an explicit enumeration value lies outside the longint range.
 +
* '''Reason''': ''Type TEnum = (a = $ffffffff);'' resulted in an enum with size 1 instead of 4 as would be expected, because  $ffffffff was interpreted as "-1".
 +
* '''Remedy''': Add Longint typecasts to values outside the valid range of a Longint.
  
−
====Result type of the ''addr()'' operator====
+
==== Comp as a type rename of Int64 instead of an alias ====
−
* '''Old behaviour''': The result type of the ''addr()'' operator was the same as that of the ''@'' operator: plain ''pointer'' in case of {$t-}, and a pointer to the argument type in case of ''{$t+}''.
+
* '''Old behavior''': On non-x86 as well as Win64 the Comp type is declared as an alias to Int64 (''Comp = Int64'').
−
* '''New behaviour''': The result type of the ''addr()'' operator is now always a plain pointer, regardless of the ''{$t+/-}'' state.
+
* '''New behavior''': On non-x86 as well as Win64 the Comp type is declared as a type rename of Int64 (''Comp = type Int64'').
−
* '''Reason''': Delphi compatibility.
+
* '''Reason''':
−
* '''Remedy''': Replace uses of ''addr()'' with ''@'' in case your code is compiled with ''{$t+}'', as this change may otherwise affect the selection of overloaded routines.
+
** This allows overloads of ''Comp'' and ''Int64'' methods/functions
 +
** This allows to better detect properties of type ''Comp''
 +
** Compatibility with Delphi for Win64 which applied the same reasoning
 +
* '''Remedy''': If you relied on ''Comp'' being able to be passed to ''Int64'' variables/parameters either include typecasts or add overloads for ''Comp''.
 +
* '''svn''': 43775
  
−
====Inaccessible symbols and properties====
+
==== Routines that only differ in result type ====
−
* '''Old behaviour''': The compiler allowed exposing normally inaccessible symbols, e.g. strict private fields from an inherited class, via properties.
+
* '''Old behaviour:''' It was possible to declare routines (functions/procedures/methods) that only differ in their result type.
−
* '''New behaviour''': Properties now obey the normal class visibility rules.
+
* '''New behaviour:''' It is no longer possible to declare routines that only differ in their result type.
−
* '''Reason''': Consistency, Delphi compatibility. See http://bugs.freepascal.org/view.php?id=14650
+
* '''Reason:''' It makes no sense to allow this as there are situations where the compiler will not be able to determine which function to call (e.g. a simple call to a function ''Foo'' without using the result).
−
* '''Remedy''': Either change the parent class and make the field or method protected, or use accessors provided by the parent class.
+
* '''Remedy:''' Correctly declare overloads.
 +
* '''Notes:'''
 +
** As the JVM allows covariant interface implementations such overloads are still allowed inside classes for the JVM target.
 +
** Operator overloads (especially assignment operators) that only differ in result type are still allowed.
 +
* '''svn:''' 45973
  
−
====<Ordinal> in <Set type> is now forbidden====
+
==== Open Strings mode enabled by default in mode Delphi ====
−
* '''Old behaviour''': Previous versions of FPC allowed type tset = 1...5;  ... if i in tset then ...
+
* '''Old behaviour:''' The Open Strings feature (directive ''$OpenStrings'' or ''$P'') was not enabled in mode Delphi.
−
* '''New behaviour''': This is now forbidden.
+
* '''New behaviour:''' The Open Strings feature (directive ''$OpenStrings'' or ''$P'') is enabled in mode Delphi.
−
* '''Reason''': Probably implemented by accident, it is not considered being valid pascal neither any other pascal compiler supports it.
+
* '''Reason:''' Delphi compatibility.
−
* '''Remedy''': Change the code into if i in [low(tset)..high(tset)]
+
* '''Remedy:''' If you have assembly routines with a ''var'' parameter of type ''ShortString'' then you also need to handle the hidden ''High'' parameter that is added for the Open String or you need to disable Open Strings for that routine.
 +
* '''git:''' [https://gitlab.com/freepascal.org/fpc/source/-/commit/188cac3bc6dc666167aacf47fedff1a81d378137 188cac3b]
  
−
====Support for class and record helpers====
+
=== Unit changes ===
−
* '''Old behaviour''': It was possible to have ''helper'' fields immediately following the ''class'' or ''record'' keyword.
 
−
* '''New behaviour''': The compiler now interprets ''helper'' as a helper type if it immediately follows the ''class'' or ''record'' keyword (the latter one only if the mode is ''delphi'' or the modeswitch ''advancedrecords'' is active).
 
−
* '''Example''':
 
−
<delphi>
 
−
{$mode delphi}
 
−
type
 
−
  TSomeRecord = class
 
−
    helper: integer;
 
−
  end;
 
−
 
 
−
  TSomeRecord = record
 
−
    helper: integer;
 
−
  end;
 
−
</delphi>
 
−
The above code will no longer compile.
 
−
* '''Reason''': ''helper'' is the way helper types are specified, which is Delphi-compatible
 
−
* '''Remedy''': Separate the ''helper'' field name from the ''class'' or ''record'' keyword with a visibility section (''published'', ''public'', ...) or with another field declaration.
 
  
−
=== Implementation changes ===
+
==== System - TVariantManager ====
  
−
====Order of parameters in RTTI====
+
* '''Old behaviour:''' ''TVariantManager.olevarfromint'' has a ''source'' parameter of type ''LongInt''.
−
* '''Old behaviour''': The order in which the parameter information for a function was stored in the RTTI depended on the function's calling convention. If the calling convention <u>on i386</u> passed parameters from left-to-right, parameters were stored from left to right (regardless of the actual platform, which was a bug in itself), otherwise they were stored from right to left.
+
* '''New behaviour:''' ''TVariantManager.olevarfromint'' has a ''source'' parameter of type ''Int64''.
−
* '''New behaviour''': The parameters are always stored from left to right in the RTTI, i.e., as they appear in the source code.
+
* '''Reason for change:''' 64-bit values couldn't be correctly converted to an OleVariant.
−
* '''Effect''': Code parsing RTTI information for the purpose of figuring out in which order to pass the parameters will no longer work.
+
* '''Remedy:''' If you implemented your own variant manager then adjust the method signature and handle the range parameter accordingly.
−
* '''Reason''': Delphi compatibility, making the information more useful for IDEs.
+
* '''svn:''' 41570
−
* '''Remedy''': Adjust your code so it always expects parameters to appear in the RTTI ordered from left to right. In the future, we will also add the calling convention itself to the RTTI (like Delphi), so you can use that information to reorder the parameters in case you want to use this information to call the routine.
 
  
−
====Sizes of sets in TP/Delphi mode====
+
==== System - buffering of output to text files ====
−
* '''Old behaviour''': {$packset fixed} was the default for all language modes. This packs a set of up to 32 elements in 4 bytes, and all other sets in 32 bytes.
 
−
* '''New behaviour''': The default in TP/Delphi mode is now {$packset 1}
 
−
* '''Effect''': In those language modes the size of sets with 1..8 elements will now be 1 byte, and the size of sets with 9..16 elements will be two bytes. Sets with 17..32 elements will remain 4 bytes, but after that every additional 8 elements the size will increase by 1 byte up to 249..256 elements, which will result in a set of 32 bytes.
 
−
* '''Reason''': TP/Delphi compatibility.
 
−
* '''Remedy''': If you have code written in TP/Delphi mode that depends on the old packset setting, add {$packset fixed} to the source (after setting the syntax mode to Delphi/TP, since the ''mode'' switching changes the ''packset'' setting). This is backward compatible with at least FPC 2.2.4 and later.
 
−
 
 
−
====Constants in mixed signed/unsigned 64 bit expressions====
 
−
* '''Old behaviour''':  Some comparisons involving a negative 64 bit constant and a unsigned 64 bit variable were handled incorrectly by the compiler: the negative constant was internally explicitly typecasted to the unsigned type.
 
−
* '''New behaviour''': The compiler will now correctly use the original value of the negative constant.
 
−
* '''Effect''': Some comparisons that previously evaluated to "true" at run time, may now evaluate to "false" at ''compile time''.
 
−
* '''Example''':
 
−
<delphi>
 
−
const
 
−
  // note that 64 bit hexadecimal constants are always parsed as int64
 
−
  // (also by previous FPC releases)
 
−
BIG_A = $AB09CD87EF653412;
 
−
var
 
−
q : qword;
 
−
begin
 
−
q := qword(BIG_A);
 
−
if (q = BIG_A) then
 
−
  writeln('same')
 
−
else
 
−
  writeln('different');
 
−
end.
 
−
</delphi>
 
−
The above program used to print 'same', but will now print 'different'
 
−
* '''Reason''': The compiler must not automatically convert negative constants to positive equivalents like that.
 
−
* '''Remedy''': Explicitly typecast any constants that are supposed to be unsigned 64 bit constants to qword. E.g., in the above example, use ''BIG_A = qword($AB09CD87EF653412)''.
 
  
−
==== Overflow/Rangechecking for floating point constants ====
+
* '''Old behaviour:''' Buffering was disabled only for output to text files associated with character devices (Linux, BSD targets, OS/2), or for output to Input, Output and StdErr regardless of their possible redirection (Win32/Win64, AIX, Haiku, BeOS, Solaris).
−
* '''Old behavior''': When a NaN floating point constant was assigned to a variable in {$R+} or {$Q+} mode, the compiler reported an error.
+
* '''New behaviour:''' Buffering is disabled for output to text files associated with character devices, pipes and sockets (the latter only if the particular target supports accessing sockets as files - Unix targets).
−
* '''New behaviour''': {$R+} and {$Q+} no longer cause errors when assigning a NaN constant to a variable. The new $ieeeerrors setting can now be used to control whether or not such assignments should cause an error.
+
* '''Reason for change:''' The same behaviour should be ensured on all supported targets whenever possible. Output to pipes and sockets should be performed immediately, equally to output to character devices (typically console) - in case of console users may be waiting for the output, in case of pipes and sockets some other program is waiting for this output and buffering is not appropriate. Seeking is not attempted in SeekEof implementation for files associated with character devices, pipes and sockets, because these files are usually not seekable anyway (instead, reading is performed until the end of the input stream is reached).
−
* '''Reason''': Consistency, Delphi compatibility (it does not support the {$ieeeerrors+/-} setting, but it does not give an error based on the {$r/q} settings either) .
+
* '''Remedy:''' Buffering of a particular file may be controlled programmatically / changed from the default behaviour if necessary. In particular, perform TextRec(YourTextFile).FlushFunc:=nil immediately after opening the text file (i.e. after calling Rewrite or after starting the program in case of Input, Output and StdErr) and before performing any output to this text to enable buffering using the default buffer, or TextRec(YourTextFile).FlushFunc:=TextRec(YourTextFile).FileWriteFunc to disable buffering.
−
* '''Remedy''': Add {$ieeeerrors+} to your code or add -C3 on the command line.
+
* '''svn:''' 46863
  
−
====New element in TTypeKind enumeration====
+
==== System - type returned by BasicEventCreate on Windows ====
−
* '''Old behaviour''': The TTypeKind enumeration contained 26 elements (''tkUnknown'' to ''tkUChar'').
 
−
* '''New behaviour''': The TTypeKind enumeration now contains 27 elements (''tkHelper'' was added at the end).
 
−
* '''Effect''': A constant array that uses TTypeKind as an index will generate a compile error, because it now contains too few elements.
 
−
* '''Reason''': Helper types needed their own type in the RTTI, because they were implemented differently than in Delphi.
 
−
* '''Remedy''': Add a new element at the end of your array with a corresponding content for helper types.
 
  
−
=== Unit changes ===
+
* '''Old behaviour:''' BasicEventCreate returns a pointer to a record which contains the Windows Event handle as well as the last error code after a failed wait. This record was however only provided in the implementation section of the  ''System'' unit.
 +
* '''New behaviour:''' BasicEventCreate returns solely the Windows Event handle.
 +
* '''Reason for change:''' This way the returned handle can be directly used in the Windows ''Wait*''-functions which is especially apparent in ''TEventObject.Handle''.
 +
* '''Remedy:''' If you need the last error code after a failed wait, use ''GetLastOSError'' instead.
 +
* '''svn:''' 49068
  
−
==== SysUtils unit changes ====
+
==== System - Ref. count of strings ====
−
* '''Old behaviour''': The ''GetAppConfigDir'' function ignored the ''VendorName''.
 
−
* '''New behaviour''': ''GetAppConfigDir'' now also takes into account ''VendorName'' if it is set.
 
−
* '''Reason''': This is in accordance with Microsoft guidelines for setting file locations.
 
−
* '''Remedy''': If you want to migrate data from the old location to the new location, you may want to temporarily clear ''VendorName'' before calling ''GetAppConfigDir'' to get the path to the old location.
 
  
−
==== xmlrpc unit and utils have been removed ====
+
* '''Old behaviour:''' Reference counter of strings was a ''SizeInt''
 +
* '''New behaviour:'''  Reference counter of strings is now a ''Longint'' on 64 Bit platforms and ''SizeInt'' on all other platforms.
 +
* '''Reason for change:''' Better alignment of strings
 +
* '''Remedy:''' Call ''System.StringRefCount'' instead of trying to access the ref. count field by pointer operations or other tricks.
 +
* '''git:''' [https://gitlab.com/freepascal.org/fpc/source/-/commit/ee10850a5793b69b19dc82b9c28342bdd0018f2e ee10850a57]
  
−
* '''Old behaviour''': There was an ''xmlrpc'' unit and a related demo program called ''mkxmlrpc''.
+
==== System.UITypes - function TRectF.Union changed to procedure ====
−
* '''New behaviour''': These sources have been removed in svn trunk, and deprecated in the svn fixes branch.
 
−
* '''Reason''': The code was unmaintained and had been broken for years, and has been replaced by new functionality in ''fcl-web'' and ''fcl-json''.
 
−
* '''Remedy''': Use fcl-web or, if adapting the source code is not feasible, obtain the xmlrpc-related sources from older FPC versions.
 
  
−
==== IInterface.QueryInterface, ._AddRef and ._Release definitions have been changed ====
+
* '''Old behaviour:''' ''function TRectF.Union(const r: TRectF): TRectF;''
 +
* '''New behaviour:'''  ''procedure TRectF.Union(const r: TRectF);''
 +
* '''Reason for change:''' Delphi compatibility and also compatibility with TRect.Union
 +
* '''Remedy:''' Call ''class function TRectF.Union'' instead.
 +
* '''git:''' [https://gitlab.com/freepascal.org/fpc/source/-/commit/5109f0ba444c85d2577023ce5fbdc2ddffc267c8 5109f0ba]
  
−
* '''Old behaviour''': The IInterface.QueryInterface, ._AddRef and ._Release methods were defined stdcall and the IID was passed as const.
+
==== 64-bit values in OleVariant ====
−
* '''New behaviour''': These methods are defined stdcall on Windows and cdecl on the other operating systems. The IID parameter has become a constref.
 
−
* '''Reason''': These methods are used for communicating with COM on Windows. These changes make it possible to interface with XPCom from Mozilla, which is cross-platform and similar to COM/Corba.
 
−
* '''Remedy''': If one of these methods is overridden, they have to be defined as follows:
 
  
−
function QueryInterface({$IFDEF FPC_HAS_CONSTREF}constref{$ELSE}const{$ENDIF} IID: TGUID; out Obj): HResult; {$IF (not defined(WINDOWS)) AND (FPC_FULLVERSION>=20501)}cdecl{$ELSE}stdcall{$IFEND}; override;
+
* '''Old behaviour:''' If a 64-bit value (''Int64'', ''QWord'') is assigned to an OleVariant its type is ''varInteger'' and only the lower 32-bit are available.
−
function _AddRef: Integer; {$IF (not defined(WINDOWS)) AND (FPC_FULLVERSION>=20501)}cdecl{$ELSE}stdcall{$IFEND}; override;
+
* '''New behaviour:''' If a 64-bit value (''Int64'', ''QWord'') is assigned to an OleVariant its type is either ''varInt64'' or ''varQWord'' depending on the input type.
−
function _Release: Integer; {$IF (not defined(WINDOWS)) AND (FPC_FULLVERSION>=20501)}cdecl{$ELSE}stdcall{$IFEND}; override;
+
* '''Reason for change:''' 64-bit values weren't correctly represented. This change is also Delphi compatible.
 +
* '''Remedy:''' Ensure that you handle 64-bit values correctly when using OleVariant.
 +
* '''svn:''' 41571
  
−
==== thread_count removed from system unit (win32,win64,wince, symbian, nativent) ====
+
==== Classes TCollection.Move ====
 +
* '''Old behaviour:''' If a TCollection.Descendant called Move() this would invoke System.Move.
 +
* '''New behaviour:''' If a TCollection.Descendant called Move() this invokes TCollection.Move.
 +
* '''Reason for change:''' New feature in TCollection: move, for consistency with other classes.
 +
* '''Remedy:'''  prepend the Move() call with the system unit name: System.move().
 +
* '''svn:''' 41795
  
−
* '''Old behaviour''': There was a variable called thread_count in the system unit of the targets win32,win64,wince, symbian, nativent
+
==== Math Min/MaxSingle/Double ====
−
* '''New behaviour''': The variable has been removed.
+
* '''Old behaviour:''' MinSingle/MaxSingle/MinDouble/MaxDouble were set to a small/big value close to the smallest/biggest possible value.
−
* '''Reason''': The behaviour of the variable was wrong and cannot be fixed, see also http://bugs.freepascal.org/view.php?id=18089
+
* '''New behaviour:''' The constants represent now the smallest/biggest positive normal numbers.
−
* '''Remedy''': Since the value of the variable was unpredictable, there was probably no use of it.
+
* '''Reason for change:''' Consistency (this is also Delphi compatibility), see https://gitlab.com/freepascal.org/fpc/source/-/issues/36870.
 +
* '''Remedy:''' If the code really depends on the old values, rename them and use them as renamed.
 +
* '''svn:''' 44714
  
−
==== Locale global variables are deprecated ====  
+
==== Random generator ====
 +
* '''Old behaviour:''' FPC uses a Mersenne twister generate random numbers
 +
* '''New behaviour:''' Now it uses Xoshiro128**
 +
* '''Reason for change:''' Xoshiro128** is faster, has a much smaller memory footprint and generates better random numbers.
 +
* '''Remedy:''' When using a certain randseed, another random sequence is generated, but as the PRNG is considered as an implementation detail, this does not hurt.
 +
* '''git:''' 91cf1774
  
−
* '''Old behaviour''': For every locale configuration a variable alias existed (currencystring, *dateformat) using an "absolute" modifier.
+
==== Types.TPointF.operator * ====
−
* '''New behaviour''': These variable now have the "deprecated" modifier, and a warning is emitted if you use one.
+
* '''Old behaviour:''' for <code>a, b: TPointF</code>, <code>a * b</code> is a synonym for <code>a.DotProduct(b)</code>: it returns a <code>single</code>, scalar product of two input vectors.
−
* '''Reason''': FPC has supported the use of these variables in a record since before 2000 called DefaultFormatSettings, Delphi XE now follows suit with "Formatsettings", and deprecated the old ones. In time this might remove the need for "absolute" usage.
+
* '''New behaviour:''' <code>a * b</code> does a component-wise multiplication and returns <code>TPointF</code>.
−
* '''Remedy''': Use (Default)Formatsettings as much as possible. Note that that it will still be quite some time before these are actually removed.
+
* '''Reason for change''': Virtually all technologies that have a notion of vectors use <code>*</code> for component-wise multiplication. Delphi with its <code>System.Types</code> is among these technologies.
 +
* '''Remedy:''' Use newly-introduced <code>a ** b</code>, or <code>a.DotProduct(b)</code> if you need Delphi compatibility.
 +
* '''git:''' [https://gitlab.com/freepascal.org/fpc/source/-/commit/f1e391fb415239d926c4f23babe812e67824ef95 f1e391fb]
  
−
==== CustApp logging changes ====
+
==== CocoaAll ====
−
* '''Old behaviour''': ''TCustomApplication.Log'' was virtual and had to be overridden to actually implement logging.
+
===== CoreImage Framework Linking =====
−
* '''New behaviour''': The ''Log'' procedure is now no longer virtual, but static.  
+
* '''Old behaviour''': Starting with FPC 3.2.0, the ''CocoaAll'' unit linked caused the ''CoreImage'' framework to be linked.
−
* '''Reason''': The new ''EventLogFilter'' property. This is a ''set of TEventType'' that determines which events are actually logged. Filtering is handled in the static ''Log'' procedure.
+
* '''New behaviour''': The ''CocoaAll'' unit no longer causes the ''CoreImage'' framework to be linked.
−
* '''Remedy''': Descendents must override the ''DoLog'' procedure instead of ''Log'' to implement the actual logging.
+
* '''Reason for change''': The ''CoreImage'' framework is not available on OS X 10.10 and earlier (it's part of ''QuartzCore'' there, and does not exist at all on some even older versions).
 +
* '''Remedy''': If you use functionality that is only available as part of the separate ''CoreImage'' framework, explicitly link it in your program using the ''{$linkframework CoreImage}'' directive.
 +
* '''svn''': 45767
  
−
==== fpweb ''T(Custom)FPWebModule.Template'' property " ====
+
==== DB ====
 +
===== TMSSQLConnection uses TDS protocol version 7.3 (MS SQL Server 2008) =====
 +
* '''Old behaviour:''' TMSSQLConnection used TDS protocol version 7.0 (MS SQL Server 2000).
 +
* '''New behaviour:''' TMSSQLConnection uses TDS protocol version 7.3 (MS SQL Server 2008).
 +
* '''Reason for change:''' native support for new data types introduced in MS SQL Server 2008 (like DATE, TIME, DATETIME2). FreeTDS client library version 0.95 or higher required.
 +
* '''svn''': 42737
  
−
* '''Old behaviour''': ''TFPWebModule''had a property ''Template''.
+
===== DB.TFieldType: new types added =====
−
* '''New behaviour''': This property has been renamed into ''ModuleTemplate''.
+
* '''Old behaviour:''' .
−
* '''Reason''': The ''TCustomFPWebModule.Template'' property was renamed to ''ModuleTemplate'' to avoid confusion with the ''Template'' property of actions in event handlers of the actions.
+
* '''New behaviour:''' Some of new Delphi field types were added (ftOraTimeStamp, ftOraInterval, ftLongWord, ftShortint, ftByte, ftExtended) + corresponding classes TLongWordField, TShortIntField, TByteField; Later were added also ftSingle and TExtendedField, TSingleField
−
* '''Remedy''': Rename ''Template'' to ''ModuleTemplate'' in all code that uses it
+
* '''Reason for change:''' align with Delphi and open space for support of short integer and unsigned integer data types
 +
* '''svn''': 47217, 47219, 47220, 47221; '''git''': c46b45bf
  
−
== Unix platforms ==
+
==== DaemonApp ====
 +
===== TDaemonThread =====
 +
* '''Old behaviour:''' The virtual method ''TDaemonThread.HandleControlCode'' takes a single ''DWord'' parameter containing the control code.
 +
* '''New behaviour:''' The virtual method ''TDaemonThread.HandleControlCode'' takes three parameters of which the first is the control code, the other two are an additional event type and event data.
 +
* '''Reason for change:''' Allow for additional event data to be passed along which is required for comfortable handling of additional control codes provided on Windows.
 +
* '''svn''': 46327
  
−
=== ''SysUtils.FileAge'' no longer works for directories ===
+
===== TDaemon =====
 +
* '''Old behaviour:''' If an event handler is assigned to ''OnControlCode'' then it will be called if the daemon receives a control code.
 +
* '''New behaviour:''' If an event handler is assigned to ''OnControlCodeEvent'' and that sets the ''AHandled'' parameter to ''True'' then ''OnControlCode'' won't be called, otherwise it will be called if assigned.
 +
* '''Reason for change:''' This was necessary to implement the handling of additional arguments for control codes with as few backwards incompatible changes as possible.
 +
* '''svn''': 46327
  
−
* '''Old behaviour''': ''SysUtils.FileAge'' worked for both files and directories on Unix platforms.
+
==== FileInfo ====
−
* '''New behaviour''': This routine now only works for files.
+
* '''Old behaviour:''' The ''FileInfo'' unit is part of the ''fcl-base'' package.
−
* '''Reason''': Consistency with other platforms, Delphi compatibility.
+
* '''New behaviour:''' The ''FileInfo'' unit is part of the ''fcl-extra'' package.
−
* '''Remedy''': Call ''BaseUnix.fpstat()'' directly for directories. A patch adding a ''DirectoryAge()'' function to ''SysUtils'' for both Unices and Windows platforms is also welcome.
+
* '''Reason for change:''' Breaks up a cycle in build dependencies after introducing a RC file parser into ''fcl-res''. This should only affect users that compile trunk due to stale PPU files in the old location or that use a software distribution that splits the FPC packages (like Debian).
 +
* '''svn''': 46392
  
−
==x86 platforms ==
+
==== Sha1 ====
 +
* '''Old behaviour:''' Sha1file silently did nothing on file not found.
 +
* '''New behaviour:''' sha1file now raises sysconst.sfilenotfound exception on fle not found.
 +
* '''Reason for change:''' Behaviour was not logical, other units in the same package already used sysutils.
 +
* '''svn''': 49166
  
−
===Operation size of pushf/popf/pusha/popa in Intel-style inline assembly===
+
==== Image ====
 +
===== FreeType: include bearings and invisible characters into text bounds =====
 +
* '''Old behaviour:''' When the bounds rect was calculated for a text, invisible characters (spaces) and character bearings (spacing around character) were ignored. The result of Canvas.TextExtent() was too short and did not include all with Canvas.TextOut() painted pixels.
 +
* '''New behaviour:''' the bounds rect includes invisible characters and bearings. Canvas.TextExtent() covers the Canvas.TextOut() area.
 +
* '''Reason for change:''' The text could not be correctly aligned to center or right, the underline and textrect fill could not be correctly painted.
 +
* '''svn''': 49629
  
−
* '''Old behaviour''': The default operation size of the ''pushf/popf/pusha/popa'' in Intel-style inline assembly was the native size (32 bit on i386, 64 bit on x86-64).
+
==== Generics.Collections & Generics.Defaults ====
−
* '''New behaviour''': The default operation size of these opcodes is now always 16 bit in Intel-style inline assembly. In AT&T-style inline assembly, the size remains the native size.
+
* '''Old behaviour:''' Various methods had '''constref''' parameters.
−
* '''Reason''': This is how the behaviour of these opcodes is defined in the Intel manuals, and it is also Delphi-compatible. The behaviour was not changed in AT&T-inline assembly because that dialect defines the default size of these operations as the native size.
+
* '''New behaviour:''' '''constref''' parameters were changed to '''const''' parameters.
−
* '''Remedy''': Explicitly specify the size when using such operations, e.g. ''pushfd'', ''popfq'', ''pushad'', ... Note that ''pusha*/popa*'' do not exist on x86-64, and neither do ''pushfd/popfd'' (the compiler previously however erroneously accepted these opcodes when compiling for x86-64).
+
* '''Reason for change:'''
 +
** Delphi compatibility
 +
** Better code generation especially for types that are smaller or equal to the ''Pointer'' size.
 +
* '''Remedy:''' Adjust parameters of method pointers or virtual methods.
 +
* '''git''': [https://gitlab.com/freepascal.org/fpc/source/-/commit/693491048bf2c6f9122a0d8b044ad0e55382354d 69349104]
  
−
==x86-64 platforms ==
+
== AArch64/ARM64 ==
 +
=== ''{''-style comments no longer supported in assembler blocks ===
 +
* '''Old behaviour''': The ''{'' character started a comment in assembler blocks, like in Pascal
 +
* '''New behaviour''': The ''{'' character now has a different meaning in the AArch64 assembler reader, so it can no longer be used to start comments.
 +
* '''Reason for change''': Support has been added for register sets in the AArch64 assembler reader (for the ld1/ld2/../st1/st2/... instructions), which also start with ''{''.
 +
* '''Remedy''': Use ''(*'' or ''//'' to start comments
 +
* '''svn''': 47116
  
−
===Parameter passing and returning results on x86-64 platforms (except for Win64)===
 
  
−
* '''Old behaviour''':  The compiler did not correctly implement the [http://www.x86-64.org/documentation/abi.pdf official x86-64 ABI] for passing parameters and returning function results in all cases. In particular, records were always either passed/returned via integer registers or memory.
+
== Darwin/iOS ==
−
* '''New behaviour''': The compiler now correctly adheres to the official x86-64 ABI under all circumstances on platforms that require this. In particular, certain records are now passed/returned via SSE registers.
 
−
* '''Effect''': Pure assembler routines based on the old conventions may no longer work on non-Win64 platforms. Win64 follows Microsoft's own variant of the x86-64 ABI and this one was already implemented correctly in the compiler, and hence has not been changed.
 
−
* '''Reason''': Interoperability with code generated by other compilers.
 
−
* '''Remedy''': Adjust your assembler code so it expects parameters to be passed conform to the official x86-64 ABI
 
  
−
===Const parameter passing on non-Win64 platforms===
+
== Previous release notes ==
 +
{{Navbar Lazarus Release Notes}}
  
−
* '''Old behaviour''': All record parameters defined as ''const'' were passed by value.
+
[[Category:FPC User Changes by release]]
−
* '''New behaviour''': For calling conventions other than ''cdecl'' and ''cppdecl'', ''const'' record parameters are now passed by reference if they should be passed via memory according to the x86-64 ABI. Note that except for ''cdecl'' and ''cppdecl'', the behaviour of ''const'' is not defined and may change at any time.
+
[[Category:Release Notes]]
−
* '''Reason''': Performance.
+
[[Category:Troubleshooting]]
−
* '''Remedy''': In most cases, this change will not require any changes to existing code. The only exception is if you have assembler routines with ''const'' record parameters. In this case, the assembler code may have to be modified to expect a pointer to the record under the circumstances mentioned above. A better modification would be to remove the ''const'' altogether from any assembler routines and either use a value parameter or [[FPC_New_Features_Trunk#Constref_parameter_modifier|constref]], which respectively guarantee passing by value and passing by reference.
 

Latest revision as of 18:32, 9 February 2024

About this page

Listed below are intentional changes made to the FPC compiler (trunk) since the previous release that may break existing code. The list includes reasons why these changes have been implemented, and suggestions for how you might adapt your code if you find that previously working code has been adversely affected by these recent changes.

The list of new features that do not break existing code can be found here.

Please add revision numbers to the entries from now on. This facilitates moving merged items to the user changes of a release.

All systems

Language Changes

Precedence of the IS operator changed

  • Old behaviour: The IS operator had the same precedence as the multiplication, division etc. operators.
  • New behaviour: The IS operator has the same precedence as the comparison operators.
  • Reason: Bug, see [1].
  • Remedy: Add parenthesis where needed.

Visibilities of members of generic specializations

  • Old behaviour: When a generic is specialized then visibility checks are handled as if the generic was declared in the current unit.
  • New behaviour: When a generic is specialized then visibility checks are handled according to where the generic is declared.
  • Reason: Delphi-compatibility, but also a bug in how visibilities are supposed to work.
  • Remedy: Rework your code to adhere to the new restrictions.

Implementation Changes

Disabled default support for automatic conversions of regular arrays to dynamic arrays

  • Old behaviour: In FPC and ObjFPC modes, by default the compiler could automatically convert a regular array to a dynamic array.
  • New behaviour: By default, the compiler no longer automatically converts regular arrays to dynamic arrays in any syntax mode.
  • Reason: When passing a dynamic array by value, modifications to its contents by the callee are also visible on the caller side. However, if an array is implicitly converted to a dynamic array, the result is a temporary value and hence changes are lost. This issue came up when adding TStream.Read() overloads.
  • Remedy: Either change the code so it no longer assigns regular arrays to dynamic arrays, or add {$modeswitch arraytodynarray}
  • Example: this program demonstrates the issue that appeared with the TStream.Read() overloads that were added (originally, only the the version with the untyped variable existed)
{$mode objfpc}
type
  tdynarray = array of byte;

procedure test(var arr); overload;
begin
  pbyte(arr)[0]:=1;
end;

procedure test(arr: tdynarray); overload;
begin
  test[0]:=1;
end;

var
  regulararray: array[1..1] of byte;
begin
  regulararray[1]:=0;
  test(arr);
  writeln(arr[0]); // writes 0, because it calls test(tdynarr)
end.
  • svn: 42118

Directive clause […] no longer useable with modeswitch PrefixedAttributes

  • Old behaviour: A function/procedure/method or procedure/method variable type could be followed by a directive clause in square brackets ([…]) that contains the directives for the routine or type (e.g. calling convention).
  • New behaviour: If the modeswitch PrefixedAttributes is enabled (which is the default in modes Delphi and DelphiUnicode) the directive clause in square brackets is no longer allowed.
  • Reason: As custom attributes are bound to a type/property in a way that looks ambiguous to a directive clause and this ambiguity is not easily solved in the parser it is better to disable this feature.
  • Remedy:
    • don't set (in non-Delphi modes) or disable modeswitch PrefixedAttributes (in Delphi modes) if you don't use attributes ({$modeswitch PrefixedAttributes-})
    • rework your directive clause:
// this
procedure Test; cdecl; [public,alias:'foo']
begin
end;

// becomes this
procedure Test; cdecl; public; alias:'foo';
begin
end;
  • svn: 42402

Type information contains reference to attribute table

  • Old behavior: The first field of the data represented by TTypeData is whatever the sub branch of the case statement for the type contains.
  • New behavior: The first field of the data represented by TTypeData is a reference to the custom attributes that are attributed to the type, only then the type specific fields follow.
  • Reason: Any type can have attributes, so it make sense to provide this is a common location instead of having to parse the different types.
  • Remedy:
    • If you use the records provided by the TypInfo unit no changes should be necessary (same for the Rtti unit).
    • If you directly access the binary data you need handle an additional Pointer field at the beginning of the TTypeData area and possibly correct the alignment for platforms that have strict alignment requirements (e.g. ARM or M68k).
  • svn: 42375

Explicit values for enumeration types are limited to low(longint) ... high(longint)

  • Old behavior: The compiler accepted every integer value as explicit enumeration value. The value was silently reduced to the longint range if it fell outside of that range
  • New behavior: The compiler throws an error (FPC mode) or a warning (Delphi mode) if an explicit enumeration value lies outside the longint range.
  • Reason: Type TEnum = (a = $ffffffff); resulted in an enum with size 1 instead of 4 as would be expected, because $ffffffff was interpreted as "-1".
  • Remedy: Add Longint typecasts to values outside the valid range of a Longint.

Comp as a type rename of Int64 instead of an alias

  • Old behavior: On non-x86 as well as Win64 the Comp type is declared as an alias to Int64 (Comp = Int64).
  • New behavior: On non-x86 as well as Win64 the Comp type is declared as a type rename of Int64 (Comp = type Int64).
  • Reason:
    • This allows overloads of Comp and Int64 methods/functions
    • This allows to better detect properties of type Comp
    • Compatibility with Delphi for Win64 which applied the same reasoning
  • Remedy: If you relied on Comp being able to be passed to Int64 variables/parameters either include typecasts or add overloads for Comp.
  • svn: 43775

Routines that only differ in result type

  • Old behaviour: It was possible to declare routines (functions/procedures/methods) that only differ in their result type.
  • New behaviour: It is no longer possible to declare routines that only differ in their result type.
  • Reason: It makes no sense to allow this as there are situations where the compiler will not be able to determine which function to call (e.g. a simple call to a function Foo without using the result).
  • Remedy: Correctly declare overloads.
  • Notes:
    • As the JVM allows covariant interface implementations such overloads are still allowed inside classes for the JVM target.
    • Operator overloads (especially assignment operators) that only differ in result type are still allowed.
  • svn: 45973

Open Strings mode enabled by default in mode Delphi

  • Old behaviour: The Open Strings feature (directive $OpenStrings or $P) was not enabled in mode Delphi.
  • New behaviour: The Open Strings feature (directive $OpenStrings or $P) is enabled in mode Delphi.
  • Reason: Delphi compatibility.
  • Remedy: If you have assembly routines with a var parameter of type ShortString then you also need to handle the hidden High parameter that is added for the Open String or you need to disable Open Strings for that routine.
  • git: 188cac3b

Unit changes

System - TVariantManager

  • Old behaviour: TVariantManager.olevarfromint has a source parameter of type LongInt.
  • New behaviour: TVariantManager.olevarfromint has a source parameter of type Int64.
  • Reason for change: 64-bit values couldn't be correctly converted to an OleVariant.
  • Remedy: If you implemented your own variant manager then adjust the method signature and handle the range parameter accordingly.
  • svn: 41570

System - buffering of output to text files

  • Old behaviour: Buffering was disabled only for output to text files associated with character devices (Linux, BSD targets, OS/2), or for output to Input, Output and StdErr regardless of their possible redirection (Win32/Win64, AIX, Haiku, BeOS, Solaris).
  • New behaviour: Buffering is disabled for output to text files associated with character devices, pipes and sockets (the latter only if the particular target supports accessing sockets as files - Unix targets).
  • Reason for change: The same behaviour should be ensured on all supported targets whenever possible. Output to pipes and sockets should be performed immediately, equally to output to character devices (typically console) - in case of console users may be waiting for the output, in case of pipes and sockets some other program is waiting for this output and buffering is not appropriate. Seeking is not attempted in SeekEof implementation for files associated with character devices, pipes and sockets, because these files are usually not seekable anyway (instead, reading is performed until the end of the input stream is reached).
  • Remedy: Buffering of a particular file may be controlled programmatically / changed from the default behaviour if necessary. In particular, perform TextRec(YourTextFile).FlushFunc:=nil immediately after opening the text file (i.e. after calling Rewrite or after starting the program in case of Input, Output and StdErr) and before performing any output to this text to enable buffering using the default buffer, or TextRec(YourTextFile).FlushFunc:=TextRec(YourTextFile).FileWriteFunc to disable buffering.
  • svn: 46863

System - type returned by BasicEventCreate on Windows

  • Old behaviour: BasicEventCreate returns a pointer to a record which contains the Windows Event handle as well as the last error code after a failed wait. This record was however only provided in the implementation section of the System unit.
  • New behaviour: BasicEventCreate returns solely the Windows Event handle.
  • Reason for change: This way the returned handle can be directly used in the Windows Wait*-functions which is especially apparent in TEventObject.Handle.
  • Remedy: If you need the last error code after a failed wait, use GetLastOSError instead.
  • svn: 49068

System - Ref. count of strings

  • Old behaviour: Reference counter of strings was a SizeInt
  • New behaviour: Reference counter of strings is now a Longint on 64 Bit platforms and SizeInt on all other platforms.
  • Reason for change: Better alignment of strings
  • Remedy: Call System.StringRefCount instead of trying to access the ref. count field by pointer operations or other tricks.
  • git: ee10850a57

System.UITypes - function TRectF.Union changed to procedure

  • Old behaviour: function TRectF.Union(const r: TRectF): TRectF;
  • New behaviour: procedure TRectF.Union(const r: TRectF);
  • Reason for change: Delphi compatibility and also compatibility with TRect.Union
  • Remedy: Call class function TRectF.Union instead.
  • git: 5109f0ba

64-bit values in OleVariant

  • Old behaviour: If a 64-bit value (Int64, QWord) is assigned to an OleVariant its type is varInteger and only the lower 32-bit are available.
  • New behaviour: If a 64-bit value (Int64, QWord) is assigned to an OleVariant its type is either varInt64 or varQWord depending on the input type.
  • Reason for change: 64-bit values weren't correctly represented. This change is also Delphi compatible.
  • Remedy: Ensure that you handle 64-bit values correctly when using OleVariant.
  • svn: 41571

Classes TCollection.Move

  • Old behaviour: If a TCollection.Descendant called Move() this would invoke System.Move.
  • New behaviour: If a TCollection.Descendant called Move() this invokes TCollection.Move.
  • Reason for change: New feature in TCollection: move, for consistency with other classes.
  • Remedy: prepend the Move() call with the system unit name: System.move().
  • svn: 41795

Math Min/MaxSingle/Double

  • Old behaviour: MinSingle/MaxSingle/MinDouble/MaxDouble were set to a small/big value close to the smallest/biggest possible value.
  • New behaviour: The constants represent now the smallest/biggest positive normal numbers.
  • Reason for change: Consistency (this is also Delphi compatibility), see https://gitlab.com/freepascal.org/fpc/source/-/issues/36870.
  • Remedy: If the code really depends on the old values, rename them and use them as renamed.
  • svn: 44714

Random generator

  • Old behaviour: FPC uses a Mersenne twister generate random numbers
  • New behaviour: Now it uses Xoshiro128**
  • Reason for change: Xoshiro128** is faster, has a much smaller memory footprint and generates better random numbers.
  • Remedy: When using a certain randseed, another random sequence is generated, but as the PRNG is considered as an implementation detail, this does not hurt.
  • git: 91cf1774

Types.TPointF.operator *

  • Old behaviour: for a, b: TPointF, a * b is a synonym for a.DotProduct(b): it returns a single, scalar product of two input vectors.
  • New behaviour: a * b does a component-wise multiplication and returns TPointF.
  • Reason for change: Virtually all technologies that have a notion of vectors use * for component-wise multiplication. Delphi with its System.Types is among these technologies.
  • Remedy: Use newly-introduced a ** b, or a.DotProduct(b) if you need Delphi compatibility.
  • git: f1e391fb

CocoaAll

CoreImage Framework Linking
  • Old behaviour: Starting with FPC 3.2.0, the CocoaAll unit linked caused the CoreImage framework to be linked.
  • New behaviour: The CocoaAll unit no longer causes the CoreImage framework to be linked.
  • Reason for change: The CoreImage framework is not available on OS X 10.10 and earlier (it's part of QuartzCore there, and does not exist at all on some even older versions).
  • Remedy: If you use functionality that is only available as part of the separate CoreImage framework, explicitly link it in your program using the {$linkframework CoreImage} directive.
  • svn: 45767

DB

TMSSQLConnection uses TDS protocol version 7.3 (MS SQL Server 2008)
  • Old behaviour: TMSSQLConnection used TDS protocol version 7.0 (MS SQL Server 2000).
  • New behaviour: TMSSQLConnection uses TDS protocol version 7.3 (MS SQL Server 2008).
  • Reason for change: native support for new data types introduced in MS SQL Server 2008 (like DATE, TIME, DATETIME2). FreeTDS client library version 0.95 or higher required.
  • svn: 42737
DB.TFieldType: new types added
  • Old behaviour: .
  • New behaviour: Some of new Delphi field types were added (ftOraTimeStamp, ftOraInterval, ftLongWord, ftShortint, ftByte, ftExtended) + corresponding classes TLongWordField, TShortIntField, TByteField; Later were added also ftSingle and TExtendedField, TSingleField
  • Reason for change: align with Delphi and open space for support of short integer and unsigned integer data types
  • svn: 47217, 47219, 47220, 47221; git: c46b45bf

DaemonApp

TDaemonThread
  • Old behaviour: The virtual method TDaemonThread.HandleControlCode takes a single DWord parameter containing the control code.
  • New behaviour: The virtual method TDaemonThread.HandleControlCode takes three parameters of which the first is the control code, the other two are an additional event type and event data.
  • Reason for change: Allow for additional event data to be passed along which is required for comfortable handling of additional control codes provided on Windows.
  • svn: 46327
TDaemon
  • Old behaviour: If an event handler is assigned to OnControlCode then it will be called if the daemon receives a control code.
  • New behaviour: If an event handler is assigned to OnControlCodeEvent and that sets the AHandled parameter to True then OnControlCode won't be called, otherwise it will be called if assigned.
  • Reason for change: This was necessary to implement the handling of additional arguments for control codes with as few backwards incompatible changes as possible.
  • svn: 46327

FileInfo

  • Old behaviour: The FileInfo unit is part of the fcl-base package.
  • New behaviour: The FileInfo unit is part of the fcl-extra package.
  • Reason for change: Breaks up a cycle in build dependencies after introducing a RC file parser into fcl-res. This should only affect users that compile trunk due to stale PPU files in the old location or that use a software distribution that splits the FPC packages (like Debian).
  • svn: 46392

Sha1

  • Old behaviour: Sha1file silently did nothing on file not found.
  • New behaviour: sha1file now raises sysconst.sfilenotfound exception on fle not found.
  • Reason for change: Behaviour was not logical, other units in the same package already used sysutils.
  • svn: 49166

Image

FreeType: include bearings and invisible characters into text bounds
  • Old behaviour: When the bounds rect was calculated for a text, invisible characters (spaces) and character bearings (spacing around character) were ignored. The result of Canvas.TextExtent() was too short and did not include all with Canvas.TextOut() painted pixels.
  • New behaviour: the bounds rect includes invisible characters and bearings. Canvas.TextExtent() covers the Canvas.TextOut() area.
  • Reason for change: The text could not be correctly aligned to center or right, the underline and textrect fill could not be correctly painted.
  • svn: 49629

Generics.Collections & Generics.Defaults

  • Old behaviour: Various methods had constref parameters.
  • New behaviour: constref parameters were changed to const parameters.
  • Reason for change:
    • Delphi compatibility
    • Better code generation especially for types that are smaller or equal to the Pointer size.
  • Remedy: Adjust parameters of method pointers or virtual methods.
  • git: 69349104

AArch64/ARM64

{-style comments no longer supported in assembler blocks

  • Old behaviour: The { character started a comment in assembler blocks, like in Pascal
  • New behaviour: The { character now has a different meaning in the AArch64 assembler reader, so it can no longer be used to start comments.
  • Reason for change: Support has been added for register sets in the AArch64 assembler reader (for the ld1/ld2/../st1/st2/... instructions), which also start with {.
  • Remedy: Use (* or // to start comments
  • svn: 47116


Darwin/iOS

Previous release notes

Lazarus - Release Notes and GIT Branch with Release Fixes

Release notes for Version:

0.9.24 | 0.9.26 | 0.9.28 | 0.9.28.2 | 0.9.30 | 1.0 | 1.2 | 1.4 | 1.6 | 1.8 | 2.0 | 2.2 | 3.0 | 4.0

Fixes branch (How to merge):

0.9 | 1.0 | 1.2 | 1.4 | 1.6 | 1.8 | 2.0 | 2.2 | 3.0

Free Pascal Compiler - User Changes (Release Notes)
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