WebAssembly/Threads
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Revision as of 00:32, 28 May 2022 by Nickysn (talk | contribs) (→Atomic instructions: - there's now a new compiler option to enable WASM threads: -CTwasmthreads, it should be used to compile the RTL, instead of -dFPC_WASM_THREADS)
Thread support
This page contains some collected informations on the features needed for thread support in WebAssembly (in the browser).
Thread support consists of 2 parts:
- Atomic instructions.
- Actually starting a thread.
Atomic instructions
When the Free Pascal RTL is compiled with -CTwasmthreads, the following RTL functions will use the new atomic instructions and thus should be thread safe in a multithreaded environment:
InterlockedDecrement InterlockedIncrement InterlockedExchange InterlockedCompareExchange InterlockedExchangeAdd
Note that these require proper alignment (4 bytes) of the target, otherwise they trap (i.e. terminate the program with a stack trace).
Thread support
Webassembly relies on the hosting environment to actually start threads.
Some extra info:
