Q32057: _beginthread()/_endthread() Coding Multi-Threaded Applications

Article: Q32057
Product(s): See article
Version(s): 5.10
Operating System(s): OS/2
Keyword(s): ENDUSER | | mspl13_c
Last Modified: 8-JUL-1988

Question:
   What do _beginthread() and _endthread() do? Do we need to use
these routines rather than the OS/2 API calls DosCreateThread() and
DosExit()? Does _beginthread() affect the stack it is passed?

Response:
   _beginthread() and _endthread() are discussed in MTDYNA.DOC.
   _beginthread() should be used in place of DosCreateThread() when
coding multi-threaded applications in C Version 5.10. _endthread()
should be used rather than DosExit() to terminate a thread before it
runs to completion.
   _beginthread() takes care of important thread-creation tasks,
such as the following:

   1. Initializing the per-thread floating-point package
   2. Saving/restoring the DGROUP environment
   3. Ensuring that there are not too many threads being created
   4. Verifying the validity of the stack generated

   The stack you pass to _beginthread() must meet the following
requirements:

   1. It must not have null segment.
   2. It must not start at an odd address.
   3. It must not have 0 length.
   4. It must not have an odd length.
   5. It must not extend past the end of the segment.

   Because of the importance of these tasks, it is important to use
_beginthread()/_endthread() instead of DosCreateThread()/ DosExit()
when coding multi-threaded applications in C Version 5.10. Although
you may be able to use DosCreateThread(), consistent results are not
guaranteed.

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