Technical Corrigendum 1 for ISO/IEC TS 17961:2013

WG 14 Document: N 2010

Date: 2016-03-01

A call to a standard memory allocation function taking a size integer argument n and presumed to be intended for type T * shall be diagnosed when n < sizeof(T).

A call to a standard memory allocation function taking a size integer argument n and presumed to be intended for type T * shall be regarded as an array of N elements, where N = n / sizeof(T).

Any allocation where N == 0 shall be diagnosed (i.e. where n < sizeof(T)). Also, any attempt to use this array in a manner that causes its array bound to be violated shall be diagnosed.

EXAMPLE In this noncompliant example, a diagnostic is required because the value of n that is used in the malloc() call has been possibly miscalculated.

wchar_t *f1(void) {
  const wchar_t *p = L"Hello, World!";
  const size_t n = sizeof(p) * (wcslen(p) + 1);
  wchar_t *q = (wchar_t *)malloc(n);  // diagnostic required

  /* ... */
  return q;
}

EXAMPLE 1 

    struct S1 {
        unsigned int x;
        float        y;
        struct S1   *z;
    };


    struct S1 *f1(void) {
        struct S1 *p = (struct S1*)malloc(sizeof(p));  // diagnostic required
        return p;
    }





EXAMPLE 2 

    wchar_t *f2(void) {
        const wchar_t *p = L"Hello, World!";
        const size_t n = (wcslen(p) + 1);
        wchar_t *q = (wchar_t *)malloc(n);
        wcscpy(q, p); // diagnostic required
        return q;
    }