mremap(2) - NetBSD Manual Pages

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MREMAP(2)                 NetBSD System Calls Manual                 MREMAP(2)


NAME

     mremap -- re-map a virtual memory address


LIBRARY

     Standard C Library (libc, -lc)


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 bound-
                        ary, i.e. ensure that the lowest n bits of the address
                        are zero.  The parameter n should be the base 2 loga-
                        rithm 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 plat-
                        form'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, fac-
                        toring in the given alignment.


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.

NetBSD 7.0                     February 14, 2008                    NetBSD 7.0