2.9BSD/usr/src/lib/c/stdio/ungetc.c

Compare this file to the similar file:
Show the results in this format:

/*	@(#)ungetc.c	2.1	SCCS id keyword	*/
#include <stdio.h>

ungetc(c, iop)
register FILE *iop;
{
	if (c == EOF)
		return(EOF);
	if ((iop->_flag&_IOREAD)==0 || iop->_ptr <= iop->_base)
		if (iop->_ptr == iop->_base && iop->_cnt==0)
			*iop->_ptr++;
		else
			return(EOF);
	iop->_cnt++;
	*--iop->_ptr = c;
	return(c);
}