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Manual Pages  — THR_kill


thr_kill – send signal to thread



Standard C Library (libc, -lc)


#include <sys/thr.h>

thr_kill(long id, int sig);

thr_kill2(pid_t pid, long id, int sig);


The thr_kill() and thr_kill2() system calls allow sending a signal, specified by the sig argument, to some threads in a process. For the thr_kill() function, signalled threads are always limited to the current process. For the thr_kill2() function, the pid argument specifies the process with threads to be signalled.

The id argument specifies which threads get the signal. If id is equal to -1, all threads in the specified process are signalled. Otherwise, only the thread with the thread identifier equal to the argument is signalled.

The sig argument defines the delivered signal. It must be a valid signal number or zero. In the latter case no signal is actually sent, and the call is used to verify the liveness of the thread.

The signal is delivered with siginfo si_code set to SI_LWP.


If successful, thr_kill() and thr_kill2() will return zero, otherwise -1 is returned, and errno is set to indicate the error.


The thr_kill() and thr_kill2() operations return the following errors:
  The sig argument is not zero and does not specify valid signal.
  The specified process or thread was not found.

Additionally, the thr_kill2() may return the following errors:
  The current process does not have sufficient privilege to check existence or send a signal to the specified process.


kill(2), thr_exit(2), thr_new(2), thr_self(2), thr_set_name(2), _umtx_op(2), pthread_kill(3), signal(3)


The thr_kill() and thr_kill2() system calls are non-standard and are used by the 1:1 Threading Library (libthr, -lthr)to implement IEEE Std 1003.1-2001 ("POSIX.1") pthread(3) functionality.

THR_kill (2) June 1, 2016

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