Windows _beginthread vs. CreateThread

Steve

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Apr 23, 2002, 10:18:48 AM4/23/02

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What is the difference between _beginthread and CreateThread? When
would I want to use one vs. the other? Why have two different ones?
Is it for backward compatibility?

Sorry if this is off topic.

Thanks for the info.
Steve

Arnold Hendriks

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Apr 23, 2002, 10:45:18 AM4/23/02

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Steve <stev...@earthlink.net> wrote:
> What is the difference between _beginthread and CreateThread? When
> would I want to use one vs. the other? Why have two different ones?
> Is it for backward compatibility?

CreateThread is the Win32 API function. _beginthread is the runtime
library's wrapper for CreateThread. You should use _beginthread, because
that gives the runtime library a chance to know that you have started
a new thread, and perhaps initialize thread-specific storage.

--
Arnold Hendriks <a.hen...@b-lex.com>
B-Lex Information Technologies, http://www.b-lex.com/

Alexander Terekhov

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Apr 23, 2002, 11:00:26 AM4/23/02

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Steve wrote:
>
> What is the difference between _beginthread and CreateThread? When
> would I want to use one vs. the other? Why have two different ones?

Are you programming in C/C++? If so...

Both are totally brain-damaged! Instead, use pthread_create():

http://sources.redhat.com/pthread-win32

regards,
alexander.

P.S. And don't miss cond.vars and other pthreads stuff too! ;-)

Alexander Terekhov

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Apr 23, 2002, 11:05:04 AM4/23/02

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Alexander Terekhov wrote:
>
> Steve wrote:
> >
> > What is the difference between _beginthread and CreateThread? When
> > would I want to use one vs. the other? Why have two different ones?
>
> Are you programming in C/C++? If so...
>
> Both are totally brain-damaged! Instead, use pthread_create():
>
> http://sources.redhat.com/pthread-win32

Oops! I meant: http://sources.redhat.com/pthreads-win32

Eric D Crahen

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Apr 23, 2002, 12:09:29 PM4/23/02

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CreateThread() will give you a thread, but won't do anything to let the
rest of the c runtime know your using a thread - so the parts that aren't
thread aware in the runtime will get screwed up unless you are very
careful about what you're doing.

_beginthreadex() will also give you a thread, but it will do some extra
work so the runtime knowns you are working with threads - which eliminates
the problems CreateThread() might introduce.

It is a little like the difference between compiling a unix program using
threads with the -DREENTRANT flag and compiling the same program w/o that
flag. There are alot of short articles about this, and I think there are
even one or two in the MSDN but I could be mistaken.

- Eric
http://www.cse.buffalo.edu/~crahen

Steve

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Apr 23, 2002, 1:23:38 PM4/23/02

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stev...@earthlink.net (Steve) wrote in message news:<21b63736.02042...@posting.google.com>...

I did a little research (I know I should have done that first) and
found an old posting, which refers to this issue. The post provides
this advice:

> In short, _beginthread/_exitthread pair for c programs that are say console
> apps that are basic and use the c-runtime lib/dll. If it's a real Win32
> app, use Win32 API's and stay away from the c-runtime. Hope this clears it
> up somewhat.

Even the MSDN section “Writing Multithreaded Win32
Programs” refers to _beginthread (including their Bounce
example). I don’t think Bounce is a Win32 program (looks like a
console program).

Any other advice on this topic? I think there is also an MFC version
of thread control, isn’t there?

Steve

Alexander Terekhov

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Apr 23, 2002, 2:45:54 PM4/23/02

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Steve wrote:

[...MSDN/Writing Multithreaded Win32 Programs/Bounce/MFC...]

> Any other advice on this topic?

YES:
http://groups.google.com/groups?as_umsgid=c29b5e33.0201240004.57d109f4%40posting.google.com

regards,
alexander.

Patrick TJ McPhee

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Apr 24, 2002, 1:42:46 AM4/24/02

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In article <Pine.SOL.4.30.02042...@hadar.cse.Buffalo.EDU>,
Eric D Crahen <cra...@cse.buffalo.edu> wrote:

% CreateThread() will give you a thread, but won't do anything to let the
% rest of the c runtime know your using a thread - so the parts that aren't
% thread aware in the runtime will get screwed up unless you are very
% careful about what you're doing.

This is a bit of a mis-statement. If you use the MS C run-time and start
a thread with CreateThread(), you may have memory leaks when the thread
exits. Being careful won't help with this, unless you're careful enough
to avoid using the C run-time.

Having said that, it's probably best to assume what Crahen says is
strictly true, up until the word `unless'.
--

Patrick TJ McPhee
East York Canada
pt...@interlog.com

Justin Michel

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Apr 25, 2002, 8:04:17 PM4/25/02

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Some libraries (MFC, ACE/TAO, C runtime, etc.) provide thread creation
functions which you must use under certain circumstances. This is usually
because the library chooses to store something in thread-specific-storage,
and can make it difficult when using these libraries together. However, it's
a common problem, so you shouldn't have any trouble finding relevant
documentation.

HTH,

Justin Michel
OCI

Jonathan de Boyne Pollard

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May 12, 2002, 2:53:13 PM5/12/02

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EDC> CreateThread() will give you a thread, but won't do anything to let the
EDC> rest of the c runtime know your using a thread - so the parts that aren't
EDC> thread aware in the runtime will get screwed up unless you are very
EDC> careful about what you're doing.

It is the parts that _are_ thread-aware that will become screwed up.