toolchain/gcc/newlib/libc/reent/lseekr.c

   1 /* Reentrant versions of lseek system call. */
   2
   3 #include <reent.h>
   4 #include <unistd.h>
   5 #include <_syslist.h>
   6
   7 /* Some targets provides their own versions of this functions.  Those
   8    targets should define REENTRANT_SYSCALLS_PROVIDED in TARGET_CFLAGS.  */
   9
  10 #ifdef _REENT_ONLY
  11 #ifndef REENTRANT_SYSCALLS_PROVIDED
  12 #define REENTRANT_SYSCALLS_PROVIDED
  13 #endif
  14 #endif
  15
  16 #ifndef REENTRANT_SYSCALLS_PROVIDED
  17
  18 /* We use the errno variable used by the system dependent layer.  */
  19 #undef errno
  20 extern int errno;
  21
  22 /*
  23 FUNCTION
  24         <<_lseek_r>>---Reentrant version of lseek
  25
  26 INDEX
  27         _lseek_r
  28
  29 ANSI_SYNOPSIS
  30         #include <reent.h>
  31         off_t _lseek_r(struct _reent *<[ptr]>,
  32                        int <[fd]>, off_t <[pos]>, int <[whence]>);
  33
  34 TRAD_SYNOPSIS
  35         #include <reent.h>
  36         off_t _lseek_r(<[ptr]>, <[fd]>, <[pos]>, <[whence]>)
  37         struct _reent *<[ptr]>;
  38         int <[fd]>;
  39         off_t <[pos]>;
  40         int <[whence]>;
  41
  42 DESCRIPTION
  43         This is a reentrant version of <<lseek>>.  It
  44         takes a pointer to the global data block, which holds
  45         <<errno>>.
  46 */
  47
  48 _off_t
  49 _DEFUN (_lseek_r, (ptr, fd, pos, whence),
  50      struct _reent *ptr _AND
  51      int fd _AND
  52      _off_t pos _AND
  53      int whence)
  54 {
  55   _off_t ret;
  56
  57   errno = 0;
  58   if ((ret = _lseek (fd, pos, whence)) == (_off_t) -1 && errno != 0)
  59     ptr->_errno = errno;
  60   return ret;
  61 }
  62
  63 #endif /* ! defined (REENTRANT_SYSCALLS_PROVIDED) */