The ``++sizeof++`` operator returns the size, in bytes, of its operand, which can be an expression or a type.


Function parameters with array types automatically decay to pointers, so it is hazardous to call the ``++sizeof++`` operator on such variables.


Moreover, calling the ``++sizeof++`` operator on a variable with pointer type is typically a mistake. Usually the intent was to get the size of the pointed-to value instead.


== Noncompliant Code Example

[source,text]
----
void clear1(int array[]) {
  for (size_t i = 0; i < sizeof(array) / sizeof(*array); i+=1) { // Noncompliant, type of array decays to int *, so sizeof(array) evaluates to sizeof(int *)
     array[i] = 0;
   }
}

void clear2(short *array, int count) {
  memset(array, sizeof(array) * count); // Noncompliant, sizeof(array) evaluates to the size of a pointer to short and not of a short
}
----


== See

* https://www.securecoding.cert.org/confluence/x/6wE[CERT, ARR01-C] - Do not apply the sizeof operator to a pointer when taking the size of an array
* https://www.securecoding.cert.org/confluence/x/9YAyAQ[CERT, CTR01-CPP] - Do not apply the sizeof operator to a pointer when taking the size of an array
* https://cwe.mitre.org/data/definitions/467[MITRE, CWE-467] - Use of sizeof() on a Pointer Type

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