newlib-cygwin/newlib/libc/reent/lseekr.c

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2000-02-18 03:39:52 +08:00
/* Reentrant versions of lseek system call. */
#include <reent.h>
#include <unistd.h>
#include <_syslist.h>
/* Some targets provides their own versions of this functions. Those
targets should define REENTRANT_SYSCALLS_PROVIDED in TARGET_CFLAGS. */
#ifdef _REENT_ONLY
#ifndef REENTRANT_SYSCALLS_PROVIDED
#define REENTRANT_SYSCALLS_PROVIDED
#endif
#endif
#ifndef REENTRANT_SYSCALLS_PROVIDED
/* We use the errno variable used by the system dependent layer. */
#undef errno
extern int errno;
/*
FUNCTION
<<_lseek_r>>---Reentrant version of lseek
INDEX
_lseek_r
ANSI_SYNOPSIS
#include <reent.h>
off_t _lseek_r(struct _reent *<[ptr]>,
int <[fd]>, off_t <[pos]>, int <[whence]>);
TRAD_SYNOPSIS
#include <reent.h>
off_t _lseek_r(<[ptr]>, <[fd]>, <[pos]>, <[whence]>)
struct _reent *<[ptr]>;
int <[fd]>;
off_t <[pos]>;
int <[whence]>;
DESCRIPTION
This is a reentrant version of <<lseek>>. It
takes a pointer to the global data block, which holds
<<errno>>.
*/
off_t
_lseek_r (ptr, fd, pos, whence)
struct _reent *ptr;
int fd;
off_t pos;
int whence;
{
off_t ret;
errno = 0;
if ((ret = _lseek (fd, pos, whence)) == (off_t) -1 && errno != 0)
ptr->_errno = errno;
return ret;
}
#endif /* ! defined (REENTRANT_SYSCALLS_PROVIDED) */