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| .\" Copyright (C) 2008 Michael Kerrisk <tmk.manpages@gmail.com> |
| .\" and Copyright 2003 Abhijit Menon-Sen <ams@wiw.org> |
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| .\" 2004-05-31, added tgkill, ahu, aeb |
| .\" 2008-01-15 mtk -- rewote DESCRIPTION |
| .\" |
| .TH TKILL 2 2008-01-15 "Linux" "Linux Programmer's Manual" |
| .SH NAME |
| tkill, tgkill \- send a signal to a thread |
| .SH SYNOPSIS |
| .nf |
| .BI "int tkill(int " tid ", int " sig ); |
| .sp |
| .BI "int tgkill(int " tgid ", int " tid ", int " sig ); |
| .fi |
| .SH DESCRIPTION |
| .BR tgkill () |
| sends the signal |
| .I sig |
| to the thread with the thread ID |
| .I tid |
| in the thread group |
| .IR tgid . |
| (By contrast, |
| .BR kill (2) |
| can only be used to send a signal to a process (i.e., thread group) |
| as a whole, and the signal will be delivered to an arbitrary |
| thread within that process.) |
| |
| .BR tkill () |
| is an obsolete predecessor to |
| .BR tgkill (). |
| It only allows the target thread ID to be specified, |
| which may result in the wrong thread being signaled if a thread |
| terminates and its thread ID is recycled. |
| Avoid using this system call. |
| |
| If |
| .I tgid |
| is specified as \-1, |
| .BR tgkill () |
| is equivalent to |
| .BR tkill (). |
| |
| These are the raw system call interfaces, meant for internal |
| thread library use. |
| .SH "RETURN VALUE" |
| On success, zero is returned. |
| On error, \-1 is returned, and \fIerrno\fP |
| is set appropriately. |
| .SH ERRORS |
| .TP |
| .B EINVAL |
| An invalid TID or signal was specified. |
| .TP |
| .B EPERM |
| Permission denied. |
| For the required permissions, see |
| .BR kill (2). |
| .TP |
| .B ESRCH |
| No process with the specified thread ID (and thread group ID) exists. |
| .SH VERSIONS |
| .BR tkill () |
| is supported since Linux 2.4.19 / 2.5.4. |
| .BR tgkill () |
| was added in Linux 2.5.75. |
| .SH "CONFORMING TO" |
| .BR tkill () |
| and |
| .BR tgkill () |
| are Linux-specific and should not be used |
| in programs that are intended to be portable. |
| .SH NOTES |
| See the description of |
| .B CLONE_THREAD |
| in |
| .BR clone (2) |
| for an explanation of thread groups. |
| |
| Glibc does not provide wrappers for these system calls; call them using |
| .BR syscall (2). |
| .SH "SEE ALSO" |
| .BR clone (2), |
| .BR gettid (2), |
| .BR gettid (2), |
| .BR kill (2) |