HP-UX Reference (11i v3 07/02) - 2 System Calls (vol 5)

munmap(2) munmap(2)

NAME

munmap - unmap pages of memory

SYNOPSIS

#include <sys/mman.h>

int munmap(void *addr, size_t len);

DESCRIPTION

The munmap() function removes the mappings for pages in the range [addr, addr+len], rounding the len

argument up to the next multiple of the page size as returned by

sysconf().Ifaddr is not the address

of a mapping established by a prior call to

mmap(), the behavior is undeﬁned. After a successful call to

munmap() and before any subsequent mapping of the unmapped pages, further references to these pages

will result in the delivery of a SIGBUS

or SIGSEGV signal to the process.

If the speciﬁed address range was created by multiple calls to

mmap(), munmap() succeeds in unmap-

ping all of the speciﬁed regions, provided they form a contiguous address range.

If the region was created with the

MAP_PRIVATE option, any modiﬁcations made to the region are dis-

carded.

RETURN VALUE

Upon successful completion,

munmap() returns 0. Otherwise, it returns −1 and sets errno to indicate

the error.

ERRORS

The

munmap() function will fails if:

[EINVAL] The addr argument is not a multiple of the page size as returned by

sysconf(_SC_PAGE_SIZE)

[EINVAL] Addresses in the range [addr, addr+len], are outside the valid range for the address

space of a process.

[EINVAL] The address range speciﬁed by addr and len was not created by a successful call to

mmap().

[EINVAL] The len argument is 0.

AUTHOR

munmap() was developed by HP, AT&T, and OSF.