Page History

...

This noncompliant code example prints the value of x as an unsigned long long value even though the value is of a programmer-defined integer type.:

#include <stdio.h>

mytypedef_t x;

/* ... */

printf("%llu", (unsigned long long) x); 

...

This compliant solution guarantees that the correct value of x is printed, regardless of its length, provided that mytypedef_t is an unsigned type.:

#include <stdio.h>
#include <inttypes.h>

mytypedef_t x;

/* ... */

printf("%ju", (uintmax_t) x);

...

The following noncompliant code example reads an unsigned long long value from standard input and stores the result in x, which is of a programmer-defined integer type.:

#include <stdio.h>

mytypedef_t x;
/* ... */
if (scanf("%llu", &x) != 1) {
  /* handle error */
}

...

This compliant solution guarantees that a correct value in the range of mytypedef_t is read, or an error condition is detected, assuming the value of MYTYPEDEF_MAX is correct as the largest value representable by mytypedef_t.:

#include <stdio.h>
#include <inttypes.h>

mytypedef_t x;
uintmax_t temp;

/* ... */

if (scanf("%ju", &temp) != 1) {
  /* handle error */
}
if (temp > MYTYPEDEF_MAX) {
  /* handle error */
}
else {
  x = temp;
} 

...

Related Vulnerabilities

Search for vulnerabilities resulting from the violation of this rule on the CERT website.

Related Guidelines

...