Manual Pages  — MUNMAP

munmap – remove a mapping

LIBRARY SYNOPSIS DESCRIPTION RETURN VALUES ERRORS SEE ALSO HISTORY

Standard C Library (libc, -lc)

#include <sys/mman.h>

int
munmap(void *addr, size_t len);

The munmap() system call deletes the mappings and guards for the specified address range, and causes further references to addresses within the range to generate invalid memory references.

The munmap function returns the value 0 if successful; otherwise the value -1 is returned and the global variable errno is set to indicate the error.

The munmap() system call will fail if:

[EINVAL]
	The addr argument was not page aligned, the len argument was zero or negative, or some part of the region being unmapped is outside the valid address range for a process.

The munmap() system call first appeared in BSD 4.4 .