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.Dd November 12, 2003 .Dt PTHREAD_SUSPEND_NP 3 .Os .Sh NAME .Nm pthread_suspend_np , .Nm pthread_resume_np .Nd suspend/resume the given thread .Sh LIBRARY .Lb libpthread .Sh SYNOPSIS n pthread.h .Ft int .Fn pthread_suspend_np "pthread_t thread" .Ft int .Fn pthread_resume_np "pthread_t thread" .Sh DESCRIPTION The .Fn pthread_suspend_np function suspends the .Ar thread given as argument. If .Ar thread is the currently running thread as returned by .Xr pthread_self 3 , the function fails and returns .Er EDEADLK . Otherwise, it removes the named thread from the running queue, and adds it to the suspended queue. The .Ar thread will remain blocked until .Fn pthread_resume_np is called on it.
p .Fn pthread_resume_np resumes the .Ar thread given as argument, if it was suspended. .Sh RETURN VALUES The .Fn pthread_suspend_np function returns 0 on success and an error number indicating the reason for the failure. The .Fn pthread_resume_np function always returns 0. .Sh ERRORS .Fn pthread_suspend_np shall fail if: l -tag -width Er t Bq Er EDEADLK The thread requested to suspend was the currently running thread. .El
p .Fn pthread_resume_np never fails. .Sh NOTES Some .Fn pthread_suspend_np implementations may allow suspending the current thread. This is dangerous, because the semantics of the function would then require the scheduler to schedule another thread, causing a thread context switch. Since that context switch can happen in a signal handler by someone calling .Fn pthread_suspend_np in a signal handler, this is currently not allowed.
p In .Fn pthread_resume_np we don't check if the .Ar thread argument is not already suspended. Some implementations might return an error condition if .Fn pthread_resume_np is called on a non-suspended thread. .Sh SEE ALSO .Xr pthread_attr_setcreatesuspend_np 3 , .Xr pthread_self 3
Indexes created Thu Oct 02 14:10:14 GMT 2025