TKILLSection: Linux Programmer's Manual (2)
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NAMEtkill, tgkill - send a signal to a single process
int tkill(int tid, int sig); int tgkill(int tgid, int tid, int sig);
DESCRIPTIONThe tkill() system call is analogous to kill(2), except when the specified process is part of a thread group (created by specifying the CLONE_THREAD flag in the call to clone). Since all the processes in a thread group have the same PID, they cannot be individually signalled with kill(2). With tkill(), however, one can address each process by its unique TID.
The tgkill() call improves on tkill() by allowing the caller to specify the thread group ID of the thread to be signalled, protecting against TID reuse. If the tgid is specified as -1, tgkill() degenerates into tkill().
RETURN VALUEOn success, zero is returned. On error, -1 is returned, and errno is set appropriately.
- An invalid TID or signal was specified.
- Permission denied. For the required permissions, see kill(2).
- No process with the specified thread ID (and thread group ID) exists.
VERSIONStkill() is supported since Linux 2.4.19 / 2.5.4. tgkill() was added in Linux 2.5.75.
CONFORMING TOtkill() and tgkill() are Linux specific and should not be used in programs that are intended to be portable.
NOTESGlibc does not provide wrapper for these system calls; call them using syscall(2).
SEE ALSOgettid(2), kill(2)