In this section:

Overview

 This error is generated when any of the following occur:

• A memory block is allocated with new and freed with free.
• A memory block is allocated with malloc and freed with delete .
• A memory block is allocated with one heap and freed with another heap.

Code Description Enabled Reported ALLOC_CONFLICT Mixing malloc/free with new/ delete Runtime (badfree) Memory was allocated with new or new[] and an attempt was made to free it with free. Runtime (baddelet) Memory was allocated with malloc and an attempt was made to free it with delete or delete[]. Runtime (badhandle) Memory is allocated by one heap and freed by a different heap Runtime

Some compilers allow you to mix new and delete with malloc and free, but this is not good programming practice and may affect portability.

Problem 1

The following code shows a typical example of allocating a block of memory with new and then freeing it with free, instead of delete.

/*
 * File: alloc1.cpp
 */
#include <stdlib.h>

int main() {
	char *a;

	a = new char;
	free(a);
	return 0;
}

Diagnosis at Runtime

[alloc1.cpp:10] **ALLOC_CONFLICT**
>>				free(a);
Memory allocation conflict: a

---- Associated Common Weakness Enumerations ----
CWE-762: Mismatched memory management routines
CWE-763: Release of invalid pointer or reference

 free() used to deallocate memory which was allocated
		using new
				a, allocated at:
				main()alloc1.cpp, 9

Stack trace where the error occurred:
				main()alloc1.cpp, 10

• Line 2: Source line at which the problem was detected.
• Line 3: Brief description of the problem.
• Lines 5-7: CWEs associated with this problem.
• Line 9: Description of the conflicting allocation/deallocation.
• Line 14: Stack trace showing the function call sequence leading to the error.

Problem 2

The following code shows another typical example of this type of error, allocating a block of memory with malloc and then freeing it with delete.

/*
 * File: alloc2.cpp
 */
 #include <stdlib.h>

 int main() {
 char *a;

 a = (char *) malloc(1);
 delete a;
 return 0;
}

Diagnosis at Runtime

[alloc2.cpp:10] **ALLOC_CONFLICT**
>> 				delete a;
Memory allocation conflict: a
 
---- Associated Common Weakness Enumerations ----
CWE-762: Mismatched memory management routines
CWE-763: Release of invalid pointer or reference

 delete operator used to deallocate memory not
	allocated by new
		block allocated at:
			malloc()(interface)
			main()alloc2.cpp, 9
Stack trace where the error occurred:
			main()alloc2.cpp, 10

• Line 2: Source line at which the problem was detected.
• Line 3: Brief description of the problem.
• Lines 5-7: CWEs associated with the problem
• Line 9: Description of the conflicting allocation/deallocation.
• Line 14: Stack trace showing the function call sequence leading to the error.

Repair

This type of error can be corrected by making sure that all your memory allocations match up.

References

The table below shows Common Weakness Enumerations associated with this error.