What is the diffrence btw memalign() and malloc()

Asked Dec 01 '16 at 07:43

Active Dec 01 '16 at 08:33

Viewed 993 times

Came across a code which allocate memory like this:

int iPage_size = getpagesize ();
int iNeedSize = (iNeedSize + iPage_size - 1) & ~(iPage_size - 1);
void* iBuffer = memalign (iPage_size, iNeedSize);

1. So why is that different from this:

void* iBuffer = malloc(iNeedSize);

2. And can I re-allocate that buffer which is allocated by memalign using realloc? or do I need to free it first and do memalign again?

Thanks.

P/s: above snippets of code is taken from a code working on V4L2-driver device.

edited Dec 01 '16 at 08:33

asked Dec 01 '16 at 07:43

Trung Nguyen

2

See previously answered question: http://stackoverflow.com/questions/6410609/when-do-we-need-to-use-posix-memalign-instead-of-malloc – ctrl-shift-esc Dec 01 '16 at 07:46
yes, it answered half of my question. How about the number 2? – Trung Nguyen Dec 01 '16 at 07:57
1

See previously answered question: http://stackoverflow.com/questions/9078259/realloc-alignment – ctrl-shift-esc Dec 01 '16 at 08:00
yep, you re right – Trung Nguyen Dec 01 '16 at 08:01
dont change your question after beeing posted. Unless you improve the wording or such but you deleted some crucial parts, please revert it. – Kami Kaze Dec 01 '16 at 08:12

0 Answers0