1 /* Copyright (C) 1991-2022 Free Software Foundation, Inc. 2 This file is part of the GNU C Library. 3 4 The GNU C Library is free software; you can redistribute it and/or 5 modify it under the terms of the GNU Lesser General Public 6 License as published by the Free Software Foundation; either 7 version 2.1 of the License, or (at your option) any later version. 8 9 The GNU C Library is distributed in the hope that it will be useful, 10 but WITHOUT ANY WARRANTY; without even the implied warranty of 11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 12 Lesser General Public License for more details. 13 14 You should have received a copy of the GNU Lesser General Public 15 License along with the GNU C Library; if not, see 16 <https://www.gnu.org/licenses/>. */ 17 18 #ifndef _SYS_FILE_H 19 #define _SYS_FILE_H 1 20 21 #include <features.h> 22 23 #ifndef _FCNTL_H 24 # include <fcntl.h> 25 #endif 26 27 __BEGIN_DECLS 28 29 30 /* Alternate names for values for the WHENCE argument to `lseek'. 31 These are the same as SEEK_SET, SEEK_CUR, and SEEK_END, respectively. */ 32 #ifndef L_SET 33 # define L_SET 0 /* Seek from beginning of file. */ 34 # define L_INCR 1 /* Seek from current position. */ 35 # define L_XTND 2 /* Seek from end of file. */ 36 #endif 37 38 39 /* Operations for the `flock' call. */ 40 #define LOCK_SH 1 /* Shared lock. */ 41 #define LOCK_EX 2 /* Exclusive lock. */ 42 #define LOCK_UN 8 /* Unlock. */ 43 44 /* Can be OR'd in to one of the above. */ 45 #define LOCK_NB 4 /* Don't block when locking. */ 46 47 48 /* Apply or remove an advisory lock, according to OPERATION, 49 on the file FD refers to. */ 50 extern int flock (int __fd, int __operation) __THROW; 51 52 53 __END_DECLS 54 55 #endif /* sys/file.h */ 56