CreateThread API Function

[Kevin Dai]

Hello all:

I want to create a thread using CreateThread API in Visual C++, below is my
code, but when I try to execute this testing program, error occurs in 7,
said that "Thread exit with code 0 ...". What's wrong?

Thanks in advance
Kevin

==>>
DWORD WINAPI MyThread(LPVOID lpParameter)
{
FILE *stream;
long i = 0;

while (i<5)
{
stream = fopen("c:\\temp\\Thread.txt", "a"); //Error in this line!
fprintf(stream, "%s, i = %d\n", "Kevin's best+++", i);
fclose(stream);
i++;
::Sleep(1000);
}
return 0;
}

void TestThread()
{
::CreateThread(NULL, NULL, &MyThread, NULL, NULL, NULL);
// MyThread(NULL);
}

[Andy Coates]

Can you give more information? What error are you seeing at the line
indicated? If there is an error how come you can debug the app? What is
calling TestThread()?

The message 'Thread exited with code 0...' is simply an informational
message indicating that a thread finished its line of execution. The code of
'0' normally means it finished without an error.

One thing that could be causing you a problem is your main thread (the one
calling TestThread()), exiting before your second thread having chance to do
its thing. If this is the case, look at using ::WaitForSingleObject() on the
handle returned from ::CreateThread() - waiting on this handle from your
main thread will stop it exiting until the second thread exits.

Andy

"Kevin Dai" <kvd...@sohu.com> wrote in message
news:esebAq6BCHA.1300@tkmsftngp04...

[Andy Moreton]

kvd...@sohu.com (Kevin Dai) wrote in <esebAq6BCHA.1300@tkmsftngp04>:

>Hello all:
>
>I want to create a thread using CreateThread API in Visual C++, below is my
>code, but when I try to execute this testing program, error occurs in 7,
>said that "Thread exit with code 0 ...". What's wrong?

You are using fopen/fprintf/fclose, which are functions from the standard C
library, not from the WIndows API. To allow the C library to be initialised
for the thread, you should use _beginthread() or _beginthreadex() instead of
CreateThread(). This is ducmented in the C library reference in VC++

Don't forget to compile and link your application with the correct options to
ensure the multithreaded version of the C library is linked with your code.

AndyM

>==>>
>DWORD WINAPI MyThread(LPVOID lpParameter)
>{
> FILE *stream;
> long i = 0;
>
> while (i<5)
> {
> stream = fopen("c:\\temp\\Thread.txt", "a"); //Error in this line!
> fprintf(stream, "%s, i = %d\n", "Kevin's best+++", i);
> fclose(stream);
> i++;
> ::Sleep(1000);
> }
> return 0;
>}
>
>void TestThread()
>{
> ::CreateThread(NULL, NULL, &MyThread, NULL, NULL, NULL);
>}

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[James Brown]

Also, CreateThread will fail under Win9X if
you don't give a valid address for the thread-identifier
to be returned into (the last parameter must not be NULL)

James

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Free win32 software, sourcecode, and tutorials
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"Kevin Dai" <kvd...@sohu.com> wrote in message
news:esebAq6BCHA.1300@tkmsftngp04...

[Kevin Dai]

Thanks you all for your excellent answers!

I now know the reason is that I am using Win32 Console Project, the main
thread will exit immediately, even before the second thread(s). I change it
to a Dialog Project, and it works fine.

Now I am going to see what ::WaitForSingleObject() will help for this case.

Thanks again
Kevin

[Kevin Dai]