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/*
** fseek.c
**
** Christian Groessler, 2000-08-07
** Ullrich von Bassewitz, 2004-05-12
*/
#include <stdio.h>
#include <errno.h>
#include <unistd.h>
#include "_file.h"
/*****************************************************************************/
/* Code */
/*****************************************************************************/
int __fastcall__ fseek (register FILE* f, long offset, int whence)
{
long res;
/* Is the file open? */
if ((f->f_flags & _FOPEN) == 0) {
_seterrno (EINVAL); /* File not open */
return -1;
}
/* If we have a pushed back character, and whence is relative to the
** current position, correct the offset.
*/
if ((f->f_flags & _FPUSHBACK) && whence == SEEK_CUR) {
--offset;
}
/* Do the seek */
res = lseek(f->f_fd, offset, whence);
/* If the seek was successful. Discard any effects of the ungetc function,
** and clear the end-of-file indicator. Otherwise set the error indicator
** on the stream, and return -1. We will check for >= 0 here, because that
** saves some code, and we don't have files with 2 gigabytes in size
** anyway:-)
*/
if (res >= 0) {
f->f_flags &= ~(_FEOF | _FPUSHBACK);
return 0;
} else {
f->f_flags |= _FERROR;
return -1;
}
}
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