posix_memalign(3) - NetBSD Manual Pages

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POSIX_MEMALIGN(3)       NetBSD 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 *).

     The aligned_alloc() function allocates size bytes of memory such that the
     allocation's base address is an even multiple of alignment.  The
     requested alignment must be a power of 2.

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


RETURN VALUES

     The posix_memalign() function returns the value 0 if successful; other-
     wise it returns an error value.

     The aligned_alloc() function returns a pointer to the allocated memory if
     successful; on failure it returns NULL and sets errno to indicate the
     error.


ERRORS

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

     [EINVAL]           The alignment parameter is not a power of 2.

     [ENOMEM]           Memory allocation error.

     The posix_memalign() function will also fail if

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

     The aligned_alloc() function will also fail if

     [EINVAL]           The size parameter is not an integer multiple of
                        alignment.


SEE ALSO

     free(3), malloc(3), realloc(3), valloc(3)


STANDARDS

     The posix_memalign() function conforms to IEEE Std 1003.1-2001
     (``POSIX.1'').  The aligned_alloc() function conforms to ISO/IEC
     9899:2018 (``ISO C18'').


HISTORY

     ISO/IEC 9899:2011 (``ISO C11'') required size to be an integer multiple
     of alignment.  This requirement was removed in later standards.

NetBSD 9.0                       July 27, 2018                      NetBSD 9.0