freebsd man page for munmap

MUNMAP(2)						      BSD System Calls Manual							 MUNMAP(2)

NAME
     munmap -- remove a mapping

LIBRARY
     Standard C Library (libc, -lc)

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
     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.

ERRORS
     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.

SEE ALSO
     madvise(2), mincore(2), mmap(2), mprotect(2), msync(2), getpagesize(3)

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

BSD
								   May 27, 1994 							       BSD