pthread_kill(3) Library Functions Manual pthread_kill(3)
NAME
pthread_kill - send a signal to a thread
LIBRARY
POSIX threads library (libpthread, -lpthread)
SYNOPSIS
#include <signal.h>
int pthread_kill(pthread_t thread, int sig);
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
pthread_kill():
_POSIX_C_SOURCE >= 199506L || _XOPEN_SOURCE >= 500
DESCRIPTION
The pthread_kill() function sends the signal sig to thread, a thread in
the same process as the caller. The signal is asynchronously directed
to thread.
If sig is 0, then no signal is sent, but error checking is still per-
formed.
RETURN VALUE
On success, pthread_kill() returns 0; on error, it returns an error num-
ber, and no signal is sent.
ERRORS
EINVAL An invalid signal was specified.
ATTRIBUTES
For an explanation of the terms used in this section, see attributes(7).
┌────────────────────────────────────────────┬───────────────┬─────────┐
│ Interface │ Attribute │ Value │
├────────────────────────────────────────────┼───────────────┼─────────┤
│ pthread_kill() │ Thread safety │ MT-Safe │
└────────────────────────────────────────────┴───────────────┴─────────┘
VERSIONS
The glibc implementation of pthread_kill() gives an error (EINVAL) on
attempts to send either of the real-time signals used internally by the
NPTL threading implementation. See nptl(7) for details.
POSIX.1-2008 recommends that if an implementation detects the use of a
thread ID after the end of its lifetime, pthread_kill() should return
the error ESRCH. The glibc implementation returns this error in the
cases where an invalid thread ID can be detected. But note also that
POSIX says that an attempt to use a thread ID whose lifetime has ended
produces undefined behavior, and an attempt to use an invalid thread ID
in a call to pthread_kill() can, for example, cause a segmentation
fault.
STANDARDS
POSIX.1-2008.
HISTORY
POSIX.1-2001.
NOTES
Signal dispositions are process-wide: if a signal handler is installed,
the handler will be invoked in the thread thread, but if the disposition
of the signal is "stop", "continue", or "terminate", this action will
affect the whole process.
SEE ALSO
kill(2), sigaction(2), sigpending(2), pthread_self(3), pthread_sig-
mask(3), raise(3), pthreads(7), signal(7)
Linux man-pages 6.9.1 2024-05-02 pthread_kill(3)
Generated by dwww version 1.16 on Tue Dec 16 03:57:45 CET 2025.