Deallocation of nonallocated memory

Overview

Use this check to detect when you call free on memory that you don’t allocate using malloc. Attempting to deallocate nonallocated memory can result in a crash. Available in Xcode 7 and later.

Deallocation of a stack variable in C

In the following example, the value variable allocates on the stack, and deallocates when the function exits, so calling free on it is incorrect:

int value = 42;
free(&value); // Error: free called on stack allocated variable

Solution

Don’t call the free function on variables that you allocate on the stack.

See Also

Address Sanitizer

• Use of deallocated memory
• Deallocation of deallocated memory
• Use of stack memory after function return
• Use of out-of-scope stack memory
• Overflow and underflow of buffers
• Overflow of C++ containers