fcup-smsend[mult]: fix buglet in K&R C NULL pointer passing The only 100% safe way to pass a NULL pointer as a function argument in K&R C is to cast 0 to a pointer type; failing to do so may cause mysterious bugs (invalid stack frames or garbage in argument registers) on 64-bit machines. This issue has already been fixed in most of FC host tools, but I just found some missed spots: passing of NULL UDH to PDU encoding functions in fcup-smsend[mult] in the case of single (not concatenated) SMS.

/*
 * This module contains the function for generating hex strings.
 */

#include <sys/types.h>
#include <stdio.h>

make_hex_string(inbuf, len, outbuf)
	u_char *inbuf;
	unsigned len;
	char *outbuf;
{
	char *dp = outbuf;
	unsigned n;

	for (n = 0; n < len; n++) {
		sprintf(dp, "%02X", inbuf[n]);
		dp += 2;
	}
	*dp = '\0';
}