Is ZeroMemory the windows equivalent of null terminating a buffer?

Question

For example I by convention null terminate a buffer (set buffer equal to zero) the following way, example 1:

char buffer[1024] = {0};

And with the windows.h library we can call ZeroMemory, example 2:

char buffer[1024];
ZeroMemory(buffer, sizeof(buffer));

According to the documentation provided by microsoft: ZeroMemory Fills a block of memory with zeros. I want to be accurate in my windows application so I thought what better place to ask than stack overflow.

Are these two examples equivalent in logic?

Why would you need to call an API function here when the C++ language does all you need. — David Heffernan, Oct 19 '20 at 13:50
@DavidHeffernan Sometimes just [to make it blindingly obvious](https://devblogs.microsoft.com/oldnewthing/20050628-07/?p=35183) ;-) — dxiv, Oct 19 '20 at 17:44
In fact, the C++ compiler is likely to convert the first (portable, standard) syntax into the appropriate API call for fast zeroing. — Ben Voigt, Oct 19 '20 at 19:59

score 1 · Accepted Answer · answered Oct 19 '20 at 18:49

Yes, the two codes are equivalent. The entire array is filled with zeros in both cases.

In the case of char buffer[1024] = {0};, you are explicitly setting only the first char element to 0, and then the compiler implicitly value-initializes the remaining 1023 char elements to 0 for you.

In C++11 and later, you can omit that first element value:

char buffer[1024] = {};
char buffer[1024]{};

Is ZeroMemory the windows equivalent of null terminating a buffer?

1 Answers1