Difference between revisions of "Character and string types"

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* [http://www.freepascal.org/docs-html/ref/refsu11.html FPC ShortString documentation]
 
* [http://www.freepascal.org/docs-html/ref/refsu11.html FPC ShortString documentation]
  
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== AnsiString ==
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Ansistrings are strings that have no length limit. They are reference counted and are guaranteed to be null terminated. Internally, a variable of type '''AnsiString''' is treated as a pointer: the actual content of the string is stored on the heap, as much memory as needed to store the string content is allocated.
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{| class="wikitable" style="text-align:center; width:300px"
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|-
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| style="width: 8%;" |  || style="width: 8%;" |  || style="width: 8%;" |  || style="width: 8%;" |  || style="width: 8%;" |  || style="width: 8%;" |  || style="width: 8%;" |  || style="width: 8%;" |  || style="width: 8%;" | a || style="width: 8%;" | b || style="width: 8%;" | c || style="width: 8%;" | #0
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|-
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| colspan="4" style="width: 16%;" | RefCount || colspan="4" style="width: 16%;" | Length
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|}
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==== Reference ====
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* [http://www.freepascal.org/docs-html/ref/refsu12.html FPC AnsiString documentation]
  
 
[[Category: FPC]]
 
[[Category: FPC]]
 
[[Category: RTL]]
 
[[Category: RTL]]
 
[[Category: Data types]]
 
[[Category: Data types]]

Revision as of 16:42, 28 December 2013

Free Pascal supports several types of characters and strings.

AnsiChar

A variable of type AnsiChar is exactly 1 byte in size, and contains one ASCII character.

a

Reference

WideChar

A variable of type WideChar is exactly 2 bytes in size, and contains one (part of) Unicode character in UTF-16 encoding. Note: it is impossible to encode all Unicode code points in 2 bytes. Therefore, 2 WideChars may be needed to encode a single code point.

a

Reference

PChar

A variable of type PChar is basically a pointer to a Char type, but allows additional operations. PChars can be used to access C-style null-terminated strings, e.g. in interaction with certain OS libraries or third-party software.

a b c #0
^

Reference

PWideChar

A variable of type PWideChar is a pointer to a WideChar variable.

a b c #0 #0
^

Reference

String

The type string may refer to ShortString or AnsiString, depending from the {$H} switch. If the switch is off ({$H-}) then any string declaration will define a ShortString. It size will be 255 chars, if not otherwise specified. If it is on ({$H+}) string without length specifier will define an AnsiString, otherwise a ShortString with specified length.

ShortString

Short strings have a maximum length of 255 characters. The length is stored in the character at index 0.

#3 a b c

Reference

AnsiString

Ansistrings are strings that have no length limit. They are reference counted and are guaranteed to be null terminated. Internally, a variable of type AnsiString is treated as a pointer: the actual content of the string is stored on the heap, as much memory as needed to store the string content is allocated.

a b c #0
RefCount Length

Reference