ack/lang/cem/libcc.ansi/sys/stdio/ftell.c
David Given 9109d7af7f First stage in modularising FILE*. Refactor so that printf/scanf don't rely on
FILE* innards; allow plats to replace the entire emulated FILE* system.
2019-06-15 13:07:10 +02:00

37 lines
650 B
C

/*
* ftell.c - obtain the value of the file-position indicator of a stream
*/
/* $Id$ */
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include "loc_incl.h"
#if ACKCONF_WANT_STDIO && ACKCONF_WANT_EMULATED_FILE
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), 0, SEEK_CUR);
if (result == -1)
return result;
result += (long)adjust;
return result;
}
#endif