NAME

posix_memalign - aligned memory allocation (ADVANCED REALTIME)

SYNOPSIS

[ADV] #include <stdlib.h>

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

DESCRIPTION

The posix_memalign() function shall allocate size bytes aligned on a boundary specified by alignment, and shall return a pointer to the allocated memory in memptr. The value of alignment shall be a power of two multiple of sizeof(void *).

Upon successful completion, the value pointed to by memptr shall be a multiple of alignment.

If the size of the space requested is 0, the behavior is implementation-defined; the value returned in memptr shall be either a null pointer or a unique pointer.

^[CX] The free() function shall deallocate memory that has previously been allocated by posix_memalign().

RETURN VALUE

Upon successful completion, posix_memalign() shall return zero; otherwise, an error number shall be returned to indicate the error.

ERRORS

The posix_memalign() function shall fail if:

[EINVAL]

The value of the alignment parameter is not a power of two multiple of sizeof(void *).

[ENOMEM]

There is insufficient memory available with the requested alignment.

EXAMPLES

None.

APPLICATION USAGE

The posix_memalign() function is part of the Advisory Information option and need not be provided on all implementations.

RATIONALE

None.

FUTURE DIRECTIONS

None.

SEE ALSO

free, malloc

XBD <stdlib.h>

CHANGE HISTORY

First released in Issue 6. Derived from IEEE Std 1003.1d-1999.

In the SYNOPSIS, the inclusion of <sys/types.h> is no longer required.

Issue 7

Austin Group Interpretation 1003.1-2001 #058 is applied, clarifying the value of the alignment argument in the DESCRIPTION.

Austin Group Interpretation 1003.1-2001 #152 is applied, clarifying the behavior when the size of the space requested is 0.