newlib-cygwin/newlib/libc/stdio64/fgetpos64.c

67 lines
1.6 KiB
C

/*
FUNCTION
<<fgetpos64>>---record position in a large stream or file
INDEX
fgetpos64
ANSI_SYNOPSIS
#include <stdio.h>
int fgetpos64(FILE *<[fp]>, _fpos64_t *<[pos]>);
TRAD_SYNOPSIS
#include <stdio.h>
int fgetpos64(<[fp]>, <[pos]>)
FILE *<[fp]>;
_fpos64_t *<[pos]>;
DESCRIPTION
Objects of type <<FILE>> can have a ``position'' that records how much
of the file your program has already read. Many of the <<stdio>> functions
depend on this position, and many change it as a side effect.
You can use <<fgetpos64>> to report on the current position for a file
identified by <[fp]> that was opened by <<fopen64>>; <<fgetpos>> will write
a value representing that position at <<*<[pos]>>>. Later, you can
use this value with <<fsetpos64>> to return the file to this
position.
In the current implementation, <<fgetpos64>> simply uses a character
count to represent the file position; this is the same number that
would be returned by <<ftello64>>.
RETURNS
<<fgetpos64>> returns <<0>> when successful. If <<fgetpos64>> fails, the
result is <<1>>. Failure occurs on streams that do not support
positioning or streams not opened via <<fopen64>>; the global <<errno>>
indicates these conditions with the value <<ESPIPE>>.
PORTABILITY
<<fgetpos64>> is a glibc extension.
No supporting OS subroutines are required.
*/
#include <stdio.h>
#ifdef __LARGE64_FILES
int
_DEFUN (fgetpos64, (fp, pos),
FILE * fp _AND
_fpos64_t * pos)
{
_flockfile(fp);
*pos = (_fpos64_t)ftello64 (fp);
if (*pos != -1)
{
_funlockfile(fp);
return 0;
}
_funlockfile(fp);
return 1;
}
#endif /* __LARGE64_FILES */