1 /* System-specific extensions of <unistd.h>, Linux version. 2 Copyright (C) 2019-2021 Free Software Foundation, Inc. 3 This file is part of the GNU C Library. 4 5 The GNU C Library is free software; you can redistribute it and/or 6 modify it under the terms of the GNU Lesser General Public 7 License as published by the Free Software Foundation; either 8 version 2.1 of the License, or (at your option) any later version. 9 10 The GNU C Library is distributed in the hope that it will be useful, 11 but WITHOUT ANY WARRANTY; without even the implied warranty of 12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 13 Lesser General Public License for more details. 14 15 You should have received a copy of the GNU Lesser General Public 16 License along with the GNU C Library; if not, see 17 <https://www.gnu.org/licenses/>. */ 18 19 #ifndef _UNISTD_H 20 # error "Never include <bits/unistd_ext.h> directly; use <unistd.h> instead." 21 #endif 22 23 #ifdef __USE_GNU 24 25 /* Return the kernel thread ID (TID) of the current thread. The 26 returned value is not subject to caching. Most Linux system calls 27 accept a TID in place of a PID. Using the TID to change properties 28 of a thread that has been created using pthread_create can lead to 29 undefined behavior (comparable to manipulating file descriptors 30 directly that have not been created explicitly). Note that a TID 31 uniquely identifies a thread only while this thread is running; a 32 TID can be reused once a thread has exited, even if the thread is 33 not detached and has not been joined. */ 34 extern __pid_t gettid (void) __THROW; 35 36 #ifdef __has_include 37 # if __has_include ("linux/close_range.h") 38 # include "linux/close_range.h" 39 # endif 40 #endif 41 /* Unshare the file descriptor table before closing file descriptors. */ 42 #ifndef CLOSE_RANGE_UNSHARE 43 # define CLOSE_RANGE_UNSHARE (1U << 1) 44 #endif 45 /* Set the FD_CLOEXEC bit instead of closing the file descriptor. */ 46 #ifndef CLOSE_RANGE_CLOEXEC 47 # define CLOSE_RANGE_CLOEXEC (1U << 2) 48 #endif 49 50 #endif /* __USE_GNU */ 51