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Re: crash if fork(2) from another thread


On Sun, Sep 28, 2008 at 09:32:39AM +0200, V??clav Haisman wrote:
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>Hirokazu Yamamoto wrote, On 28.9.2008 4:16:
>> # I've post mail, but it didn't show up in
>> http://www.nabble.com/Cygwin-f12165.html.
>> # Maybe it was not good to attach a file. So try again...
>> 
>> I'm not familiar with pthread & fork, but I think following code should not
>> crash. Is this expected behavior?
>> 
>> #include <stdio.h>
>> #include <stdlib.h>
>> #include <pthread.h>
>> #include <assert.h>
>> 
>> void *thread_func(void* args)
>> {
>>     int ret;
>>     pid_t pid;
>>     pthread_t thread;
>> 
>>     puts("thread_func");
>> 
>>     pid = fork();
>> 
>>     assert(pid != (pid_t)-1);
>> 
>>     if (pid != 0) /* parent process */
>>     {
>>         int status;
>> 
>>         printf("parent process (child pid = %d)\n", pid);
>> 
>>         waitpid(pid, &status, 0);
>> 
>>         puts("parent process end");
>>     }
>>     else /* child process */
>>     {
>>         puts("child process"); /* crash here */
>I think this is not allowed in here.  You can only do async-signal-safe
>stuff in the child.  IO is AFAIK not in that category.  Basically, the
>only thing you can safely do in the child process is to call exec().

I don't see any reason why this shouldn't be allowed.  You should
be able to do anything you want in a child process.

cgf

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