NAME

posix_memalign — aligned memory allocation

SYNOPSIS

#include <stdlib.h>

int
posix_memalign(void **memptr, 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 exact multiple of alignment, and returns the allocation in the value pointed to by memptr.

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). (Note however, that the allocation returned by realloc(3) or reallocf(3) is not guaranteed to preserve the original alignment).

NOTES

posix_memalign() should be used judiciously as the algorithm that realizes the alignment constraint can incur significant memory overhead.

RETURN VALUES

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

ERRORS

The posix_memalign() function 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), malloc_zone_memalign(3)

STANDARDS

The posix_memalign() function conforms to IEEE Std 1003.1-2001 (“POSIX.1”).