table of contents
- wheezy 3.44-1
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|SET_TID_ADDRESS(2)||Linux Programmer's Manual||SET_TID_ADDRESS(2)|
NAME¶set_tid_address - set pointer to thread ID
#include <linux/unistd.h>long set_tid_address(int *tidptr);
DESCRIPTION¶For each process, the kernel maintains two attributes (addresses) called set_child_tid and clear_child_tid. These two attributes contain the value NULL by default.
- If a process is started using clone(2) with the CLONE_CHILD_SETTID flag, set_child_tid is set to the value passed in the ctid argument of that system call.
- When set_child_tid is set, the very first thing the new process does is writing its PID at this address.
- If a process is started using clone(2) with the CLONE_CHILD_CLEARTID flag, clear_child_tid is set to the value passed in the ctid argument of that system call.
futex(clear_child_tid, FUTEX_WAKE, 1, NULL, NULL, 0);
RETURN VALUE¶set_tid_address() always returns the PID of the calling process.
ERRORS¶set_tid_address() always succeeds.
VERSIONS¶This call is present since Linux 2.5.48. Details as given here are valid since Linux 2.5.49.
CONFORMING TO¶This system call is Linux-specific.
SEE ALSO¶clone(2), futex(2)
COLOPHON¶This page is part of release 3.44 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/.