glibc/sysdeps/unix/sysv/linux/bits/unistd_ext.h

37 lines
1.6 KiB
C

/* System-specific extensions of <unistd.h>, Linux version.
Copyright (C) 2019-2020 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#ifndef _UNISTD_H
# error "Never include <bits/unistd_ext.h> directly; use <unistd.h> instead."
#endif
#ifdef __USE_GNU
/* Return the kernel thread ID (TID) of the current thread. The
returned value is not subject to caching. Most Linux system calls
accept a TID in place of a PID. Using the TID to change properties
of a thread that has been created using pthread_create can lead to
undefined behavior (comparable to manipulating file descriptors
directly that have not been created explicitly). Note that a TID
uniquely identifies a thread only while this thread is running; a
TID can be reused once a thread has exited, even if the thread is
not detached and has not been joined. */
extern __pid_t gettid (void) __THROW;
#endif