Windows threading: _beginthread vs _beginthreadex vs CreateThread C++

Question

What\'s a better way to start a thread, _beginthread, _beginthreadx or CreateThread?

I\'m trying to determine what are the adv

Answer 1

Looking at the function signatures, CreateThread is almost identical to _beginthreadex.

_beginthread, _beginthreadx vs CreateThread

HANDLE WINAPI CreateThread(
  __in_opt   LPSECURITY_ATTRIBUTES lpThreadAttributes,
  __in       SIZE_T dwStackSize,
  __in       LPTHREAD_START_ROUTINE lpStartAddress,
  __in_opt   LPVOID lpParameter,
  __in       DWORD dwCreationFlags,
  __out_opt  LPDWORD lpThreadId
);

uintptr_t _beginthread( 
   void( *start_address )( void * ),
   unsigned stack_size,
   void *arglist 
);

uintptr_t _beginthreadex( 
   void *security,
   unsigned stack_size,
   unsigned ( *start_address )( void * ),
   void *arglist,
   unsigned initflag,
   unsigned *thrdaddr 
);

The remarks on here say _beginthread can use either __cdecl or __clrcall calling convention as start point, and _beginthreadex can use either __stdcall or __clrcall for start point.

I think any comments people made on memory leaks in CreateThread are over a decade old and should probably be ignored.

Interestingly, both _beginthread* functions actually call CreateThread under the hood, in C:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\crt\src on my machine.

// From ~line 180 of beginthreadex.c
/*
 * Create the new thread using the parameters supplied by the caller.
 */
if ( (thdl = (uintptr_t)
      CreateThread( (LPSECURITY_ATTRIBUTES)security,
                    stacksize,
                    _threadstartex,
                    (LPVOID)ptd,
                    createflag,
                    (LPDWORD)thrdaddr))
         == (uintptr_t)0 )
{
        err = GetLastError();
        goto error_return;
}