kolibrios-fun/programs/develop/ktcc/trunk/libc/stdio/ungetc.c
siemargl 524cab3cd8 added read buffering, ungetc
git-svn-id: svn://kolibrios.org@7184 a494cfbc-eb01-0410-851d-a64ba20cac60
2018-03-12 20:41:06 +00:00

33 lines
581 B
C

#include <stdio.h>
// non standard realization - support for virtually change ONLY ONE char
int ungetc(int c,FILE* file)
{
dword res;
if(!file)
{
errno = E_INVALIDPTR;
return EOF;
}
if ((file->mode & 3) != FILE_OPEN_READ && (file->mode & FILE_OPEN_PLUS) == 0)
{
errno = E_ACCESS;
return EOF;
}
if (file->filepos > file->filesize || file->filepos == 0 || c == EOF || file->ungetc_buf != EOF)
{
errno = E_EOF;
return EOF;
}
file->ungetc_buf = c;
file->filepos--;
return c;
}