1 /* An interface to read() that retries after interrupts. 2 Copyright (C) 2002, 2006, 2009-2021 Free Software Foundation, Inc. 3 4 This file is free software: you can redistribute it and/or modify 5 it under the terms of the GNU Lesser General Public License as 6 published by the Free Software Foundation; either version 2.1 of the 7 License, or (at your option) any later version. 8 9 This file 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 12 GNU Lesser General Public License for more details. 13 14 You should have received a copy of the GNU Lesser General Public License 15 along with this program. If not, see <https://www.gnu.org/licenses/>. */ 16 17 /* Some system calls may be interrupted and fail with errno = EINTR in the 18 following situations: 19 - The process is stopped and restarted (signal SIGSTOP and SIGCONT, user 20 types Ctrl-Z) on some platforms: Mac OS X. 21 - The process receives a signal for which a signal handler was installed 22 with sigaction() with an sa_flags field that does not contain 23 SA_RESTART. 24 - The process receives a signal for which a signal handler was installed 25 with signal() and for which no call to siginterrupt(sig,0) was done, 26 on some platforms: AIX, HP-UX, IRIX, OSF/1, Solaris. 27 28 This module provides a wrapper around read() that handles EINTR. */ 29 30 #include <stddef.h> 31 32 #ifdef __cplusplus 33 extern "C" { 34 #endif 35 36 37 #define SAFE_READ_ERROR ((size_t) -1) 38 39 /* Read up to COUNT bytes at BUF from descriptor FD, retrying if interrupted. 40 Return the actual number of bytes read, zero for EOF, or SAFE_READ_ERROR 41 upon error. */ 42 extern size_t safe_read (int fd, void *buf, size_t count); 43 44 45 #ifdef __cplusplus 46 } 47 #endif