- Unreal Engine 4.x Scripting with C++ Cookbook
- John P. Doran William Sherif Stephen Whittle
- 238字
- 2025-02-28 12:28:30
How it works...
The preceding code does what is shown in the diagram that follows:
- The first line creates an int * pointer variable, i, which starts as a dangling pointer referring to a segment of memory that probably won't be valid for your program to reference.
- In the second step of the diagram, we use a malloc() call to initialize the variable i to point to a segment of memory precisely the size of an int variable, which will be valid for your program to refer to.
- We then initialize the contents of that memory segment to the value 0 using the command *i = 0;. Refer to the following diagram:
Note the difference between the assignment to a pointer variable ( i = ), which tells the pointer which memory address to refer to, and the assignment to what it is inside the memory address that the pointer variable refers to ( *i = ).
When the memory in the variable i needs to be released back to the system, we do so using a free() de-allocation call, as shown in the following diagram. i is then assigned to point to the memory address, 0, shown in this diagram by the electrical grounding symbol reference, 
:
The reason we set the variable i to point to the NULL reference is to make it clear that the variable i does not refer to a valid segment of memory.