(void addr, size_t length, int prot, int flags, int fd, off_t offset)

void  

Creates a mapping between the virtual address space of the calling process and a file or device.

munmap (void addr, size_t length)

int 

Removes all mappings for the specified virtual address space.

(void addr, size_t len, int prot)

int 

Sets protection attributes for the memory pages contained in the memory region starting from addr with the specified length.

mremap (void old_address, size_t old_size, size_t new_size, int flags,…)

Remaps a virtual memory region.