/* 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