To claim and return the memory zones to the system used mmap() and munmap() syscals. To make it tread-safe pthread_mutex_t is used. Functions prototyped just like the systems ones:
void *malloc(size_t size);void *realloc(void *ptr, size_t size);void free(void *ptr);-
The
malloc()function allocates “size” bytes of memory and returns a pointer to the allocated memory. -
The
realloc()function tries to change the size of the allocation pointed to by “ptr” to “size”, and returns “ptr”. If there is not enough room to enlarge the memory allocation pointed to by ptr, realloc() creates a new allocation, copies as much of the old data pointed to by “ptr” as will fit to the new allocation, frees the old allocation, and returns a pointer to the allocated memory. -
The
free()function deallocates the memory allocation pointed to by “ptr”. If “ptr”is a NULL pointer, no operation is performed. -
In case of an error, the
malloc(),realloc()functions return a NULL pointer.
Main information sources were:
- Modern Operating Systems (4th Edition) by Andrew S. Tanenbaum, Herbert Bos
- man (2) mmap
- man (3) munmap
