__after_morecore_hook - Linux
Overview
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.
Syntax
void __after_morecore_hook(void *ptr, size_t size);
Options/Flags
None.
Examples
Consider the following code snippet:
#include <stdlib.h>
__attribute__((constructor))
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.
Integration
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.