ungetc(3)

NAME
     ungetc - push character back into input stream

SYNOPSIS
     #include <stdio.h>

     int ungetc(int c, FILE *stream)

DESCRIPTION
     Ungetc pushes the character c back on an input  stream.   That  character
     will be returned by the next getc call on that stream.  Ungetc returns c.

     One character of pushback is guaranteed provided something has been  read
     from  the  stream  and the stream is actually buffered.  Attempts to push
     EOF are rejected.

     Fseek(3) erases all memory of pushed back characters.

SEE ALSO
     getc(3), setbuf(3), fseek(3).

DIAGNOSTICS
     Ungetc returns EOF if it can't push a character back.