Re: [c++-pthreads] Problem in type conversion in pthread_create

[Steve Clamage <Stephen.Clamage@xxxxxxx>]

Function pthread_create is a C function, and needs to be passed the
address of an ordinary function with C linkage.

You are attempting to pass it the address of what appears to be a class
member function. The address of a class member function is not an
ordinary pointer-to-function, and is incompatible with
pointer-to-function.  In any event, the function you are passing has C++
linkage.

You need to create global functions with C linkage for passing to
pthread_create. Those function can be written in C++, and can use C++
features.

---
Steve Clamage, stephen.clamage@xxxxxxx

Abhijit Tendulkar wrote:
> Hello,
> 
> I'm new to this list, this is my first post.
> 
> I'm getting the type conversion error in my program.
> I tried it in following way.
> 
> This is the function in which threads are to be
> created:
> 
> void MonteCarlo :: generateEnrmap(vector<string> vstr,
> int ns, float svdw, float er)
> {
>         arg ar, *arptr;
>         //void *arptr;
>         void *ptr;
>         pthread_t id;
>         int mid = _pgrmap.size() / 2;
>         ar.vstr = vstr;
>         ar.ns = ns;
>         ar.svdw = svdw;
>         ar.er = er;
>         ar.mid = mid;
>         //arptr = &ar;
>         ptr = &ar; //arptr;
>         if( 0 == pthread_create(&id, NULL,
> generateEnrmap1, ptr) ) //Line No. 416
>                 cout<<"First thread created.\n";
>         if( 0 == pthread_create(&id, NULL,
> generateEnrmap2, ptr) ) //Line No. 418
>                 cout<<"Second thread created.\n";
>         pthread_exit(NULL);
> }
> 
> These are prototypes of two functions used in threads.
> void * MonteCarlo :: generateEnrmap1(void *ptr)
> void * MonteCarlo :: generateEnrmap2(void *ptr)
> 
> The only error I'm getting is as follows.
> 
> -bash-2.05b$ make
> g++  -c -lpthread source/MonteCarlo.cc -Iheader
> source/MonteCarlo.cc: In member function `void
>    MonteCarlo::generateEnrmap(std::vector<std::string,
>    std::allocator<std::string> >, int, float, float)':
> source/MonteCarlo.cc:416: error: argument of type
> `void*(MonteCarlo::)(void*)'
>    does not match `void*(*)(void*)'
> source/MonteCarlo.cc:418: error: argument of type
> `void*(MonteCarlo::)(void*)'
>    does not match `void*(*)(void*)'
> make: *** [MonteCarlo.o] Error 1
> -bash-2.05b$
> 
> Can anybody please help me in removing this error?
> why this error message is showing one more * in
> bracket?
> 
> Waiting for reply.
> 
> Thanks & regards.
> 
> Abhijit
> 
> 
> 		
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