posix_memalign(3p) [suse man page]

POSIX_MEMALIGN(3P)					     POSIX Programmer's Manual						POSIX_MEMALIGN(3P)

PROLOG

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

NAME

       posix_memalign - aligned memory allocation (ADVANCED REALTIME)

SYNOPSIS

       #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 multiple of sizeof( void *), that is also a power of two. Upon successful
       completion, the value pointed to by memptr shall be a multiple of alignment.

       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.

       The following sections are informative.

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(), the Base Definitions volume of IEEE Std 1003.1-2001, <stdlib.h>

COPYRIGHT

       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for Information Technol-
       ogy -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
       Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between this version and  the  original  IEEE
       and  The  Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained
       online at http://www.opengroup.org/unix/online.html .

IEEE
/The Open Group						       2003							POSIX_MEMALIGN(3P)

POSIX_MEMALIGN(3)					     Linux Programmer's Manual						 POSIX_MEMALIGN(3)

NAME

       posix_memalign, memalign, valloc - Allocate aligned memory

SYNOPSIS

       #include <stdlib.h>

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

DESCRIPTION

       The function posix_memalign() allocates size bytes and places the address of the allocated memory in *memptr.  The address of the allocated
       memory will be a multiple of alignment, which must be a power of two and a multiple of sizeof(void *).

       The obsolete function memalign() allocates size bytes and returns a pointer to the allocated memory.  The memory address will be a multiple
       of boundary, which must be a power of two.

       The  obsolete  function valloc() allocates size bytes and returns a pointer to the allocated memory.  The memory address will be a multiple
       of the page size.  It is equivalent to memalign(sysconf(_SC_PAGESIZE),size).

       For all three routines, the memory is not zeroed.

RETURN VALUE

       memalign() and valloc() return the pointer to the allocated memory, or NULL if the request fails.

       posix_memalign() returns zero on success, or one of the error values listed in the next section on failure. Note that errno is not set.

ERRORS

       EINVAL The alignment parameter was not a power of two, or was not a multiple of sizeof(void *).

       ENOMEM There was insufficient memory to fulfill the allocation request.

NOTES

       posix_memalign() verifies that alignment matches the requirements detailed above.  memalign() may not check that the boundary parameter	is
       correct.

       POSIX  requires	that memory obtained from posix_memalign() can be freed using free().  Some systems provide no way to reclaim memory allo-
       cated with memalign() or valloc() (because one can only pass to free() a pointer gotten from malloc(), while e.g.   memalign()  would  call
       malloc() and then align the obtained value).  GNU libc allows memory obtained from any of these three routines to be reclaimed with free().

       GNU libc malloc() always returns 8-byte aligned memory addresses, so these routines are only needed if you require larger alignment values.

AVAILABILITY

       The  functions  memalign()  and valloc() have been available in all Linux libc libraries.  The function posix_memalign() is available since
       glibc 2.1.91.

CONFORMING TO

       The function valloc() appeared in 3.0 BSD. It is documented as being obsolete in BSD 4.3, and as legacy in SUSv2. It no	longer	occurs	in
       SUSv3.  The function memalign() appears in SunOS 4.1.3 but not in BSD 4.4.  The function posix_memalign() comes from POSIX 1003.1d.

SEE ALSO

       malloc(3), free(3), getpagesize(2), brk(2)

GNU
								    2001-10-11							 POSIX_MEMALIGN(3)