Is array allocated on heap set to zero?

nibbler · 12-13-2005, 03:32 PM

Hello,

I've heard that in C an array allocated on heap is set to zero ( and it worked so far ), although I know that it is generally not true for stack allocation. If it is true, why is this so? Is it true for linux, or is it defined in the ANSI C? I haven't found the answer on google, so any link would be great.

Thanks in advance

tuxdev · 12-13-2005, 03:43 PM

It is the same reason that a pointer could point to some random value, but primitives are initialized to something predictable.

nibbler · 12-14-2005, 02:50 AM

I'm not sure I understand. If by primitives you think basic data types such as int or double, those aren't set to zero in C ( when declared on stack, and I'm wondering is it true for heap ).

IBall · 12-14-2005, 02:55 AM

I would say never assume. The gcc compiler might, the Borland C compiler might not. If you always initialise all your variables properly, then you always know that they have been initialised.

--Ian