source: trunk/minix/lib/stdio/ftell.c@ 20

/*
 * ftell.c - obtain the value of the file-position indicator of a stream
 */
/* $Header: /cvsup/minix/src/lib/stdio/ftell.c,v 1.1.1.1 2005/04/21 14:56:35 beng Exp $ */

#include        <stdio.h>

#if     (SEEK_CUR != 1) || (SEEK_SET != 0) || (SEEK_END != 2)
#error SEEK_* values are wrong
#endif

#include        "loc_incl.h"

#include        <sys/types.h>

off_t _lseek(int fildes, off_t offset, int whence);

long ftell(FILE *stream)
{
        long result;
        int adjust = 0;

        if (io_testflag(stream,_IOREADING))
                adjust = -stream->_count;
        else if (io_testflag(stream,_IOWRITING)
                    && stream->_buf
                    && !io_testflag(stream,_IONBF))
                adjust = stream->_ptr - stream->_buf;
        else adjust = 0;

        result = _lseek(fileno(stream), (off_t)0, SEEK_CUR);

        if ( result == -1 )
                return result;

        result += (long) adjust;
        return result;
}