ultrix man page for ungetc

ungetc(3s)																ungetc(3s)

Name
       ungetc - push character back into input stream

Syntax
       #include <stdio.h>

       ungetc(c, stream)
       FILE *stream;

Description
       The  routine pushes the character c back on an input stream.  That character will be returned by the next call on that stream.  The routine
       returns c.  One character of pushback is guaranteed in all cases.

       The routine erases all memory of pushed back characters.

Diagnostics
       The routine returns EOF if it cannot push a character back.

Environment
       In POSIX mode, the file's EOF indicator is cleared.

See Also
       fseek(3s), getc(3s), setbuf(3s)

																	ungetc(3s)