[fpc-devel] calls to Fpc-made library from C not thread-safe

[Vlad]

> Hi,
> 
> I have a library compiled with Fpc, used from C/C++ programs.
> When these C programs call functions of the library from different threads, things break.
> 
> As I understand it, the exception stack(s), the standard input/output streams, the threadID and stack checking variables use thread variables, and when the thread is created from C, this variables are not allocated nor initialized.
> 
> As a workaround, I thought I could export a function from the library, to be called in each thread before any other library call, which would call CurrentTM.AllocateThreadVars and System.InitThread.
> And symetrically, a function to be called after any other library call in the thread, which flushes the input/output streams and calls CurrentTM.ReleaseThreadVars.
> 
> Does that sound correct?
> 
> Dominique
> 

Hi

I'm in similar situation under Mac OS X.
I have to create dummy thread when library loaded and then to use such functions in additional threads:

procedure thread_init;
var
  TM: TThreadManager;
begin
  GetThreadManager(TM);
  TM.AllocateThreadVars;
  InitThread(500000); // 500000 is the stack size, all threads have 512Kb stack, not sure must here be exact stack size or not.
end;

procedure thread_done;
var
  TM: TThreadManager;
begin
  GetThreadManager(TM);
  TM.ReleaseThreadVars;
end;