MREMAP(2)

NAME
mremap - re-map a virtual memory address

LIBRARY
libc

SYNOPSIS
#include <sys/mman.h>
void *
mremap(void *oldp, size_t oldsize, void *newp, size_t newsize, int flags);

DESCRIPTION
The mremap() function resizes the mapped range (see mmap(2)) starting at oldp and having size oldsize to newsize. The following arguments can be OR'ed together in the flags argument:

MAP_ALIGNED(n)
    The allocation should be aligned to the given boundary, i.e. ensure that the lowest n bits of the address are zero. The parameter n should be the base 2 logarithm of the desired alignment (e.g., to request alignment to 16K, use 14 as the value for n). The alignment must be equal to or greater than the platform's page size as returned by sysconf(3) with the _SC_PAGESIZE request.

MAP_FIXED
    newp is tried and mremap() fails if that address can't be used as new base address for the range. Otherwise, oldp and newp are used as hints for the position, factoring in the given alignment.

MAP_REMAPDUP
    Duplicate the mapping. Both address ranges reference the same pages, but can have different protection flags.

RETURN VALUES
mremap() returns the new address or MAP_FAILED, if the remap failed.

COMPATIBILITY
The semantics of mremap() differ from the one provided by glibc on Linux in that the newp argument was added and a different set of flags are implemented.

SEE ALSO
mmap(2), munmap(2)

HISTORY
The mremap() system call appeared in NetBSD 5.0. It was based on the code that supports mremap() compatibility for Linux binaries.