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POSIX_MEMALIGN(3)     DragonFly Library Functions Manual     POSIX_MEMALIGN(3)

NAME
     posix_memalign, aligned_alloc -- aligned memory allocation

LIBRARY
     Standard C Library (libc, -lc)

SYNOPSIS
     #include <stdlib.h>

     int
     posix_memalign(void **ptr, size_t alignment, size_t size);

     void *
     aligned_alloc(size_t alignment, size_t size);

DESCRIPTION
     The posix_memalign() function allocates size bytes of memory such that
     the allocation's base address is an even multiple of alignment, and
     returns the allocation in the value pointed to by ptr.

     The requested alignment must be a power of 2 at least as large as
     sizeof(void *).

     Memory that is allocated via posix_memalign() can be used as an argument
     in subsequent calls to realloc(3), reallocf(3), and free(3).

     The aligned_alloc() is similar to posix_memalign(), but it does not have
     the sizeof(void *) restriction, takes just alignment and size and the
     allocation pointer is returned.

IMPLEMENTATION NOTES
     The posix_memalign() function is directly supported by matching the
     requested alignment against a zone of the slab allocator with a
     compatible chunking, and using the power-of-2 shortcut whenever possible.
     Alignments beyond those supported by the zone mechanism are still
     guaranteed using cute mmap(2) tricks.  Our posix_memalign() is thus able
     to take advantage of the slab allocator to produce well-fitted results
     when the requests are reasonable.

RETURN VALUES
     The posix_memalign() function returns the value 0 if successful;
     otherwise it returns an error value.  The aligned_alloc() returns a
     pointer to the allocated memory if successful; otherwise a NULL pointer
     is returned and errno is set.

ERRORS
     The posix_memalign() and aligned_alloc() functions will fail if:

     [EINVAL]           The alignment parameter is not a power of 2 at least
                        as large as sizeof(void *).

     [ENOMEM]           Memory allocation error.

SEE ALSO
     free(3), malloc(3), realloc(3), reallocf(3), valloc(3)

STANDARDS
     The posix_memalign() function conforms to IEEE Std 1003.1-2008
     (``POSIX.1'').  The aligned_alloc() function conforms to ISO/IEC
     9899:2011 (``ISO C11'').

DragonFly 5.5                    April 7, 2019                   DragonFly 5.5