Is memcpy a system call?

Thanks in advnace,

memcpy is *not* a system call. It is a standard C library function. System calls are those where you enter the kernel mode and ask your OS to do something for you (like read/write from disk). For memory copy you don't need to take the service of OS.

On Sat, Jun 09, 2012 at 12:11:36AM +0900, J.Hwan Kim wrote:

Hi, everyone

Is memcpy a system call?

Thanks in advnace,

Best Regards, J.Hwna Kim

"strace" is a good tool to find out which system calls a program is doing. To answer your question, I don't think it makes much sense to implement memcpy as a syscall, because entering kernel mode is usually relatively expensive and I can't think of any kernel mode-only memcpy optimizations (and optimizations are the only reason to do a user space memcpy in kernel space I can think of). HTH, Jonathan Neuschäfer