bin/75638: sscanf %lld broken on 4.x

[Pawel Malachowski]

>Number:         75638
>Category:       bin
>Synopsis:       sscanf %lld broken on 4.x
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Wed Dec 29 23:00:46 GMT 2004
>Closed-Date:
>Last-Modified:
>Originator:     Pawe³ Ma³achowski
>Release:        FreeBSD 4.11-STABLE i386
>Organization:
ZiN
>Environment:
System: FreeBSD 4.11-STABLE #20: Sat Dec 18 19:32:41 CET 2004

	
>Description:
sscanf(s, "%lld", &l) will not set l to valid value if l was previously
not zero.

For example, ports/net-mgmt/iftop `max-bandwidth' option is broken on 4.x because of this.

>How-To-Repeat:

#include <stdio.h>
void main(void) {
  char *s = "10";
  long long l;
  int rc = 0;
  rc = sscanf(s, "%lld", &l);
  fprintf(stderr, "rc %d, s %s, l %lld\n", rc, s, l);
}

output on 4.x:
rc 1, s 10, l -4629710020483743734

output on 5.3:
rc 1, s 10, l 10

>Fix:

Workaround: set lld value to zero before using it with sscanf (noticed by venglin).

#include <stdio.h>
void main(void) {
  char *s = "10";
  long long l = 0;
  int rc = 0;
  rc = sscanf(s, "%lld", &l);
  fprintf(stderr, "rc %d, s %s, l %lld\n", rc, s, l);
}

output on 4.x:
rc 1, s 10, l 10
 
>Release-Note:
>Audit-Trail:
>Unformatted: