TKILL(2) Linux Programmer's Manual TKILL(2)

tkill, tgkill - send a signal to a single process

int tkill(int tid, int sig);

int tgkill(int tgid, int tid, int sig);

The 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(2)). Since all the processes in a thread group have the same PID, they cannot be individually signaled 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 signaled, protecting against TID reuse. If the tgid is specified as -1, tgkill() degenerates into tkill().

These are the raw system call interfaces, meant for internal thread library use.

On 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.

tkill() is supported since Linux 2.4.19 / 2.5.4. tgkill() was added in Linux 2.5.75.

tkill() and tgkill() are Linux specific and should not be used in programs that are intended to be portable.

Glibc does not provide wrapper for these system calls; call them using syscall(2).

gettid(2), kill(2)

This page is part of release 2.69 of the Linux man-pages project. A description of the project, and information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.

2007-06-01 Linux

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