Synopsis

Detect and handle standard library errors.

Enabled by default

Yes

Severity/Certainty

High/High

Full description

The majority of the standard library functions, including I/O functions and memory allocation functions, return either a valid value or a value of the correct return type that indicates an error (for example, -1 or a null pointer). It is essential that programs detect and appropriately handle all errors in accordance with an error-handling policy.

Coding standards

Code examples

The following code example fails the check and will give a warning:

#include <stdlib.h>

void *p;
void func(size_t new_size) {
    if (new_size == 0) {
        /* Handle error */
    }
    p = realloc(p, new_size);
    if (p == NULL) {
        /* Handle error */
    }
}

The following code example passes the check and will not give a warning about this issue:

#include <stdlib.h>

void *p;
void func(size_t new_size) {
    void *q;

    if (new_size == 0) {
        /* Handle error */
    }

    q = realloc(p, new_size);
    if (q == NULL) {
        /* Handle error */
    } else {
        p = q;
    }
}