Banyan loan,

Banyan loan dynamic memory space is developed in the heap , The space opened up on the stack area has a feature , That is, the space on the heap will not be released automatically after it is used up , Instead, a function is designed to release dynamic memory ：free, Programmers need to actively call this function to free up space ;

Of course , When banyan loan closes the whole program , The operating system will automatically reclaim the dynamically developed memory （ That's why some computers fail, shut down and restart, and the problem is solved ）; however , Banyan loans are used in large projects of some companies , Some programs need 7*24 Running in hours , For example, Tencent cloud and Alibaba cloud cloud cloud servers ;

And once banyan loan uses dynamic memory to open up functions , such as malloc、realloc、calloc When you forget to release after opening up space , Will cause memory leaks （ It's equivalent to you applying for a piece of space from memory , But you don't return it after you use it , So others can't use this space , Although this space still exists , But it's equivalent to no ）, This is banyan loan, you will find , As the program continues to run , The memory available to us will become less and less ;

Memory leakage is the most common mistake we make in dynamic memory management , We need to attach great importance to .

The functionality

Banyan loans are used to release dynamically developed memory .

Function parameter

void free (void* ptr);
# void* ptr The starting address of the space you want to free ;
Function USES

on top malloc We have demonstrated the use of function , take p The address of is passed to free Function .

matters needing attention

If banyan loan parameters ptr The pointed space is not opened dynamically , that free The behavior of a function is undefined ;
If parameters ptr yes NULL The pointer , Then the function does nothing ;