[fpc-pascal] Mangle name in fpc-FreeBSD ?

[Marc Santhoff]

On Sa, 2016-03-19 at 14:39 -0700, fredvs wrote:
> @ Marco and Marc thanks for help.
> 
> Sorry I do not have easy internet connection so I worked by my side.
> 
> I will try your tips.
> 
> By the way, here are my investigations:
> 
> ____________________________________
> 
> Hello.
> 
> Ok, ok, understood and wow.
> 
> Added in code:
> 
>     Function dlopen(filename: PChar; flags: cint): Pointer; cdecl; external;
>     Function dlclose(handle: Pointer): cint; cdecl; external;
>     Function dlsym(handle: Pointer; Name: PChar): Pointer; cdecl; external;
>     Function dlerror: PChar; cdecl; external;
> 
> and, magic, it works. ;-)
> 
> Now the result:
> 
> In code:
> 
> procedure loadmylib(lib : pchar);
> var
> ap1, ap2, ap3 : pointer;
> '
> begin
> /// FreeBSD functions:
> ap1 := dlopen(Pchar(lib), 0);

Here you are using 0 for three mode argument. One difference I can see
ist that uysing dynlibs.pas the mode is RTLD_LAZY like it should be, but
that constant is defined as 1.

Does anyone now if this really makes a difference?

> if ap1 <> nil then
> writeln('dlopen() is OK') else
> writeln('dlopen() is NOT OK') ;
> 
> ap2 := dlsym(ap1, Pchar('mp4ff_open_read');
> if ap2 <> nil then
> writeln('dlsym() is OK') else
> writeln('dlsym() is NOT OK') ;
> 
> writeln(dlerror());
> 
> end;
> 
> ---> result:
> writeln('dlopen() is OK')
> writeln('dlsym() is OK')
> _ (no error)
> 
> --------------------------------------
> Now with DynLibs:
> 
> procedure loadmylib(lib : pchar);
> var
> ap1: pointer;
> hn : integer;
> '
> begin
> /// with dynlibs
> hn := dynlibs.loadlibrary(Pchar(lib));
> 
> if hn <> 0 then
> writeln('loadlibrary() is OK') else
> writeln('loadlibrary() is NOT OK') ;
> 
> ap1 := getprocedureaddress(hn, Pchar('mp4ff_open_read');
> 
> if ap1 <> nil then
> writeln('getprocedureaddress() is OK') else
> writeln('getprocedureaddress() is NOT OK') ;

Looking at dynlibs.pas you can use

  Function GetLoadErrorStr: string;

here. Or simply dlerror() like in the other program, should work.


> end;
> 
> --> result:
> 
> loadlibrary() is OK
> getprocedureaddress() is NOT OK
> 
> ............
>  
> Conclusion: Maybe getprocedureaddress() has problems.

-- 
Marc Santhoff <M.Santhoff at web.de>