posix_memalign()
QNX SDP8.0C Library ReferenceAPIDeveloper
Allocate aligned memory
Synopsis:
#include <stdlib.h>
int posix_memalign( void ** memptr,
size_t alignment,
size_t size );
Arguments:
- memptr
- A pointer to a location where posix_memalign() can store a pointer to the memory.
- alignment
- The alignment to use for the memory.
This must be a multiple of
sizeof( void * )that's also a power of 2. - size
- The size, in bytes, of the block to allocate.
Library:
libc
Use the -l c option to qcc to link against this library. This library is usually included automatically.
Description:
The posix_memalign() function allocates size bytes aligned on a boundary specified by alignment. It returns a pointer to the allocated memory in memptr.
The buffer allocated by posix_memalign() is contiguous in virtual address space, but not physical memory. Since some platforms don't allocate memory in 4 KB page sizes, you shouldn't assume that the memory allocated will be physically contiguous if you specify a size of 4 KB or less.
You can obtain the physical address of the start of the buffer using mem_offset() with fd=NOFD.
Returns:
- 0
- Success.
- EINVAL
- The value of alignment isn't a multiple of
sizeof( void * )that's also a power of 2. - ENOMEM
- There's insufficient memory available with the requested alignment.
Classification:
| Safety: | |
|---|---|
| Cancellation point | No |
| Signal handler | No |
| Thread | Yes |
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