hello,

when i use fork with my program , the program waits in the pselect

untill the child process ends.

why?

Do you mean that you expect pselect() to return for some other reason, but it gets stuck there until a child ends?

Or do you mean that an ending child causes the pselect() to return earlier than you expected?

If it's the second of those two, you have enabled signal SIGCHLD in the signal mask parameter to the pselect(). Whenever a child ends, the parent's process will receive signal SIGCHLD if that signal is enabled in the parent process.

i mean that the pselect get stuck until the child process ends.

and i need the father process will continue working while the child still works.

There's no inherent reason that pselect() should hang until the child process ends. This sounds like a standard debugging situation.

If playing with the program doesn't reveal the problem, then as I see it you have two ways to go.

The first way would be to set aside the code as it exists now, make a playing copy of the code, and in that playing copy rip out things until the pselect() works. This can consume a lot of time.

The second way can also consume a lot of time. Write a simple program from scratch which demonstrates that pselect() works. Then add a child process to that simple code, and see that pselect() still works. Then add more and more of your original features until you discover where pselect() doesn't work any more.

But maybe someone else on lq has a better idea. I'm hoping someone does.

well , i found the problam

i had a probalm in my sigchild

i didnt use waitpid as i should use it.

thanks for all.

closed.

Usually that sort of problem happens if the parent fails to close the end of a pipe/socket that it won't be using.
ta0kira

Correct. Either that, or the child fails to do this.