posix_memalign man page


This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (consult the corresponding Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.

posix_memalign — aligned memory allocation (ADVANCED REALTIME)


#include <stdlib.h>

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


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.

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.


The posix_memalign() function shall fail if:

The value of the alignment parameter is not a power of two multiple of sizeof(void *).
There is insufficient memory available with the requested alignment.

The following sections are informative.

Application Usage

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

See Also

free(), malloc()

The Base Definitions volume of POSIX.1‐2008, <stdlib.h>