maximum buffer size allowed in memcpy

[ram619]

What is the maximum buffer size allowed in memecpy() function in c, I am using GCC compiler,32-bit system, What is the affecting factor for memcpy failure?

->Alignment issue?
->Size?

however the buffer size 256bytes not working, tried 160 bytes copy which fits our requirement

[Suzie999]

http://stackoverflow.com/questions/745152/what-is-the-maximum-size-of-buffers-memcpy-memset-etc-can-handle

[ram619]

Thanks for the relpy. I went through the webpage but still have a doubt.
On my system size_t is of 4 byte. As it is unsigned so 2^32
= 4294967296. Means this many bits size_t could hold and hence memcpy() can copy only this much size of data ???

[Suzie999]

To be honest I don't know, and never knew there was a max.

If I needed to know however, I'd probably test it starting with that value. Or just divide and rule.

[Hiroshe]

Best way would probably be to test it out and see for yourself. Close anything important, open your proccess manager, and just keep increasing it until it stops working!

[deceptikon]

To be honest I don't know, and never knew there was a max.

That's because it's high enough that if you reach it, you're doing something very very wrong. ;)

[Suzie999]

Sounds about right.

If there no official limit, I'd guess that the max would be the amount of free memory currenly available.

[deceptikon]

If there no official limit, I'd guess that the max would be the amount of free memory currenly available.

There's an official limit: the range of size_t. Obviously if you cannot tell memcpy to copy more than (size_t)-1 bytes, then that's the limit in a single call. Copying more than that requires multiple calls, but on a modern system size_t is typically either 32 or 64 bits. So the limit is quite large.

[ram619]

Thanks Everyone for the prompt replies.
Ideally size_t should be able to hold quite large amount of memory. I think I need to check the code, may be somewhere something else is going wrong.