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#include "stdio_impl.h"
#include <wchar.h>
#include <limits.h>
#include <ctype.h>
#include <string.h>
wint_t ungetwc(wint_t c, FILE *f)
{
unsigned char mbc[MB_LEN_MAX];
int l=1;
if (c == WEOF) return c;
/* Try conversion early so we can fail without locking if invalid */
if (!isascii(c) && (l = wctomb((void *)mbc, c)) < 0)
return WEOF;
FLOCK(f);
f->mode |= f->mode+1;
if ((!f->rend && __toread(f)) || f->rpos < f->buf - UNGET + l) {
FUNLOCK(f);
return EOF;
}
if (isascii(c)) *--f->rpos = c;
else memcpy(f->rpos -= l, mbc, l);
f->flags &= ~F_EOF;
FUNLOCK(f);
return c;
}
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