munmap(2) System Calls Manual munmap(2)
Name
munmap - unmaps memory of a character device
Syntax
#include <sys/types.h>
#include <sys/mman.h>
caddr_t munmap(addr, len)
caddr_t addr;
size_t len;
Arguments
addr Specifies the address space of the calling process at which the unmapping begins.
len Specifies the number of bytes to unmap.
Description
The system call unmaps a specified number of bytes (len) starting at a specified address (addr) from the address space of the calling
process. You mapped this device in a previous call to Subsequent access to the unmapped region results in a signal. You cannot unmap
data, stack, and text segments using
The system call rounds len to the nearest multiple of page size as returned by
The range [addr, addr + len] may contain more than one mapped region created by In this case, unmaps all of the mapped regions.
Restrictions
All of the mapped regions must be wholly contained in the range [addr, addr + len]. That is, addr must be the beginning of some mapped
region and addr + len must be the end of some (possibly different) mapped region.
Return Value
If successful, returns 0. Otherwise, it returns -1 and sets the errno argument to one of the errors listed in the Diagnostics section.
Diagnostics
The call to fails if one or more of the following is true:
[EINVAL] The address you specified in addr is not a multiple of the page size as returned by
[EINVAL] The addresses in the range [addr, addr + len] are not valid in the process address space.
[EINVAL] All of the segments being unmapped are not entirely contained in the range [addr, addr + len].
See Also
getpagesize(2), getsysinfo(2), mmap(2)
munmap(2)
