1#include "stdio_impl.h"
2
3int __overflow(FILE* f, int _c) {
4    unsigned char c = _c;
5    if (!f->wend && __towrite(f))
6        return EOF;
7    if (f->wpos < f->wend && c != f->lbf)
8        return *f->wpos++ = c;
9    if (f->write(f, &c, 1) != 1)
10        return EOF;
11    return c;
12}
13