rm_/lib/safe-read.h

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/* An interface to read() that retries after interrupts.
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Copyright (C) 2002, 2006, 2009-2022 Free Software Foundation, Inc.
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This file 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.
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This file is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with this program. If not, see <https://www.gnu.org/licenses/>. */
/* Some system calls may be interrupted and fail with errno = EINTR in the
following situations:
- The process is stopped and restarted (signal SIGSTOP and SIGCONT, user
types Ctrl-Z) on some platforms: Mac OS X.
- The process receives a signal for which a signal handler was installed
with sigaction() with an sa_flags field that does not contain
SA_RESTART.
- The process receives a signal for which a signal handler was installed
with signal() and for which no call to siginterrupt(sig,0) was done,
on some platforms: AIX, HP-UX, IRIX, OSF/1, Solaris.
This module provides a wrapper around read() that handles EINTR. */
#include <stddef.h>
#ifdef __cplusplus
extern "C" {
#endif
#define SAFE_READ_ERROR ((size_t) -1)
/* Read up to COUNT bytes at BUF from descriptor FD, retrying if interrupted.
Return the actual number of bytes read, zero for EOF, or SAFE_READ_ERROR
upon error. */
extern size_t safe_read (int fd, void *buf, size_t count);
#ifdef __cplusplus
}
#endif