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IAR Embedded Workbench for RL78 5.20

MEM-leak-alias

In this section:
Synopsis

Incorrect deallocation causes memory leak.

Enabled by default

Yes

Severity/Certainty

Medium/Medium

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Full description

Memory is allocated, but then the pointer value is lost due to reassignment or its scope ending, without a guarantee of the value being propagated or the memory being freed. There must be no possible execution path during which the value is not freed, returned, or passed into another function as an argument, before it is lost. This is a memory leak. Note: If alias analysis is disabled, you must enable the non-alias version of this check, MEM-leak. This check is identical to MISRAC2012-Dir-4.13_b.

Coding standards
CERT MEM31-C

Free dynamically allocated memory exactly once

CWE 401

Improper Release of Memory Before Removing Last Reference ('Memory Leak')

CWE 772

Missing Release of Resource after Effective Lifetime

MISRA C:2012 Dir-4.13

(Advisory) Functions which are designed to provide operations on a resource should be called in an appropriate sequence

Code examples

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

#include <stdlib.h>

int main(void) {
  int *ptr = (int *)malloc(sizeof(int));
  
  ptr = NULL; //losing reference to the allocated memory

  free(ptr);

  return 0;
}

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

#include <stdlib.h>

int main(void) {
    int *ptr = (int*)malloc(sizeof(int));
    if (rand() < 5) {
        free(ptr);
    } else {
        free(ptr);
    }
    return 0;
}