NAME
pthread_suspend_np,
pthread_resume_np
—
suspend/resume the given thread
LIBRARY
POSIX Threads Library (libpthread, -lpthread)
SYNOPSIS
#include <pthread.h>
int
pthread_suspend_np(
pthread_t
thread);
int
pthread_resume_np(
pthread_t
thread);
DESCRIPTION
The
pthread_suspend_np() function suspends the
thread given as argument. If
thread is the currently running thread as returned by
pthread_self(3), the
function fails and returns
EDEADLK
. Otherwise, it
removes the named thread from the running queue, and adds it to the suspended
queue. The
thread will remain blocked until
pthread_resume_np() is called on it. In other words,
pthread_resume_np() resumes the
thread
given as argument, if it was suspended.
RETURN VALUES
Both functions return 0 on success and an error number indicating the reason for
the failure.
COMPATIBILITY
These functions are non-standard extensions.
ERRORS
The
pthread_suspend_np() function may fail if:
-
-
- [
EDEADLK
]
- The thread requested to suspend was the currently running
thread.
-
-
- [
ESRCH
]
- The supplied thread was invalid.
The
pthread_resume_np() function may fail if:
-
-
- [
ESRCH
]
- The supplied thread was invalid.
NOTES
Some
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
pthread_suspend_np() in a signal handler,
this is currently not allowed.
In
pthread_resume_np() the
NetBSD
implementation does not check if the
thread argument is
not already suspended. Some implementations might return an error condition if
pthread_resume_np() is called on a non-suspended thread.
SEE ALSO
pthread_attr_setcreatesuspend_np(3),
pthread_self(3)