NAME

munmap — remove a mapping

SYNOPSIS

#include <sys/mman.h>

int
munmap(void *addr, size_t len);

DESCRIPTION

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

RETURN VALUES

Upon successful completion, the value 0 is returned; otherwise the value -1 is returned and the global variable errno is set to indicate the error.

ERRORS

munmap() will fail if:

[EINVAL]

The addr and len parameters specify a region that would extend beyond the end of the address space, or some part of the region being unmapped is not part of the currently valid address space.

SEE ALSO

madvise(2), mlock(2), mlockall(2), mmap(2), mprotect(2), msync(2), getpagesize(3)

STANDARDS

When len is non-zero, the munmap() function conforms to IEEE Std 1003.1-2008 (“POSIX.1”).

HISTORY

The munmap() system call has been available since 4.3BSD-Net/2.

CAVEATS

IEEE Std 1003.1-2008 (“POSIX.1”) specifies that munmap() shall fail with EINVAL if len is 0. OpenBSD performs no action in this case.