__after_morecore_hook - Linux


The __after_morecore_hook function allows post-processing the memory address returned by __morecore(). It is primarily used in low-level memory management systems to enhance memory allocation and deallocation operations.


void __after_morecore_hook(void *ptr, size_t size);




Consider the following code snippet:

#include <stdlib.h>

static void init() {
    __after_morecore_hook = post_processing_function;

static void post_processing_function(void *ptr, size_t size) {
    // Perform custom operations on the allocated memory
    // (e.g., tracking, security checks)

int main() {
    // Allocate memory using malloc, which internally uses __morecore
    void *mem = malloc(1024);

    // The allocated memory will be post-processed by the hook function
    __after_morecore_hook(mem, 1024);

In this example, the post_processing_function is registered as the __after_morecore_hook using an attribute constructor. When memory is allocated using malloc, the post-processing function is invoked, allowing custom actions to be performed on the newly allocated memory.

Common Issues

  • Hook not registered: Ensure that the hook function is properly registered before allocating memory.
  • Invalid memory address: Verify that the memory address returned by __morecore() is valid and accessible.


The __after_morecore_hook can be used in conjunction with other memory management functions, such as mmap and brk, to create custom memory allocation strategies or perform specific tasks during memory allocation.

Related Commands

  • __morecore: Requests additional memory from the operating system.
  • mmap: Maps a file or device into memory.
  • brk: Adjusts the end of the data segment.