|MUNMAP(3P)||POSIX Programmer's Manual||MUNMAP(3P)|
int munmap(void *addr, size_t len);
The implementation may require that addr be a multiple of the page size as returned by sysconf().
If a mapping to be removed was private, any modifications made in this address range shall be discarded.
Any memory locks (see mlock() and mlockall()) associated with this address range shall be removed, as if by an appropriate call to munlock().
If a mapping removed from a typed memory object causes the corresponding address range of the memory pool to be inaccessible by any process in the system except through allocatable mappings (that is, mappings of typed memory objects opened with the POSIX_TYPED_MEM_MAP_ALLOCATABLE flag), then that range of the memory pool shall become deallocated and may become available to satisfy future typed memory allocation requests.
A mapping removed from a typed memory object opened with the POSIX_TYPED_MEM_MAP_ALLOCATABLE flag shall not affect in any way the availability of that typed memory for allocation.
The behavior of this function is unspecified if the mapping was not established by a call to mmap().
- Addresses in the range [addr,addr+len) are outside the valid range for the address space of a process.
- The len argument is 0.
The munmap() function may fail if:
- The addr argument is not a multiple of the page size as returned by sysconf().
The following sections are informative.
It is possible that an application has applied process memory locking to a region that contains shared memory. If this has occurred, the munmap() call ignores those locks and, if necessary, causes those locks to be removed.
Most implementations require that addr is a multiple of the page size as returned by sysconf().
The Base Definitions volume of POSIX.1‐2017, <sys_mman.h>
Any typographical or formatting errors that appear in this page are most likely to have been introduced during the conversion of the source files to man page format. To report such errors, see https://www.kernel.org/doc/man-pages/reporting_bugs.html .
|2017||IEEE/The Open Group|