third_party/ulib/musl/src/stdio/__overflow.c

#include "stdio_impl.h"

int __overflow(FILE* f, int _c) {
    unsigned char c = _c;
    if (!f->wend && __towrite(f))
        return EOF;
    if (f->wpos < f->wend && c != f->lbf)
        return *f->wpos++ = c;
    if (f->write(f, &c, 1) != 1)
        return EOF;
    return c;
}