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cc65/libsrc/common/ftell.c

47 lines
963 B
C

/*
* ftell.c
*
* Christian Groessler, 2000-08-07
* Ullrich von Bassewitz, 2004-05-13
*/
#include <stdio.h>
#include <errno.h>
#include <unistd.h>
#include "_file.h"
/*****************************************************************************/
/* Code */
/*****************************************************************************/
long __fastcall__ ftell (register FILE* f)
{
long pos;
/* Is the file open? */
if ((f->f_flags & _FOPEN) == 0) {
_seterrno (EINVAL); /* File not open */
return -1L;
}
/* Call the low level function */
pos = lseek (f->f_fd, 0L, SEEK_CUR);
/* If we didn't have an error, correct the return value in case we have
* a pushed back character.
*/
if (pos > 0 && (f->f_flags & _FPUSHBACK)) {
--pos;
}
/* -1 for error, comes from lseek() */
return pos;
}