toolchain/gcc/newlib/libc/stdio64/fsetpos64.c

   1 /*
   2 FUNCTION
   3 <<fsetpos64>>---restore position of a large stream or file
   4
   5 INDEX
   6         fsetpos64
   7 INDEX
   8         _fsetpos64_r
   9
  10 ANSI_SYNOPSIS
  11         #include <stdio.h>
  12         int fsetpos64(FILE *<[fp]>, const _fpos64_t *<[pos]>);
  13         int _fsetpos64_r(struct _reent *<[ptr]>, FILE *<[fp]>,
  14                          const _fpos64_t *<[pos]>);
  15
  16 TRAD_SYNOPSIS
  17         #include <stdio.h>
  18         int fsetpos64(<[fp]>, <[pos]>)
  19         FILE *<[fp]>;
  20         _fpos64_t *<[pos]>;
  21
  22         int _fsetpos64_r(<[ptr]>, <[fp]>, <[pos]>)
  23         struct _reent *<[ptr]>;
  24         FILE *<[fp]>;
  25         _fpos64_t *<[pos]>;
  26
  27 DESCRIPTION
  28 Objects of type <<FILE>> can have a ``position'' that records how much
  29 of the file your program has already read.  Many of the <<stdio>> functions
  30 depend on this position, and many change it as a side effect.
  31
  32 You can use <<fsetpos64>> to return the large file identified by <[fp]> to a
  33 previous position <<*<[pos]>>> (after first recording it with <<fgetpos64>>).
  34
  35 See <<fseeko64>> for a similar facility.
  36
  37 RETURNS
  38 <<fgetpos64>> returns <<0>> when successful.  If <<fgetpos64>> fails, the
  39 result is <<1>>.  The reason for failure is indicated in <<errno>>:
  40 either <<ESPIPE>> (the stream identified by <[fp]> doesn't support
  41 64-bit repositioning) or <<EINVAL>> (invalid file position).
  42
  43 PORTABILITY
  44 <<fsetpos64>> is a glibc extension.
  45
  46 Supporting OS subroutines required: <<close>>, <<fstat>>, <<isatty>>,
  47 <<lseek64>>, <<read>>, <<sbrk>>, <<write>>.
  48 */
  49
  50 #include <stdio.h>
  51
  52 #ifdef __LARGE64_FILES
  53
  54 int
  55 _DEFUN (_fsetpos64_r, (ptr, iop, pos),
  56         struct _reent *ptr _AND
  57         FILE * iop _AND
  58         _CONST _fpos64_t * pos)
  59 {
  60   int x = _fseeko64_r (ptr, iop, (_off64_t)(*pos), SEEK_SET);
  61
  62   if (x != 0)
  63     return 1;
  64   return 0;
  65 }
  66
  67 #ifndef _REENT_ONLY
  68
  69 int
  70 _DEFUN (fsetpos64, (iop, pos),
  71         FILE * iop _AND
  72         _CONST _fpos64_t * pos)
  73 {
  74   return _fsetpos64_r (_REENT, iop, pos);
  75 }
  76
  77 #endif /* !_REENT_ONLY */
  78
  79 #endif /* __LARGE64_FILES */