Thanks for the info.

I didn't know that we were making a distinction between different kinds of
variables in the earlier discussion, but I can see how it is important.
Probably my Turbo C++ isn't completely ANSI compatible because I seem to
remember defining global arrays and upon inspecting them,finding only the
portion that I actually set being initialized,the rest containing "random"
data.

Actually, I just went and tried it,and lo and behold,it IS initializing
global arrays to zero. I stand corrected, must be my memory playing tricks
on me ;-)

Oh, BTW, another C question for the experts: Is this legal ANSI C?

#include <stdio.h>

void main ( void )
{
        printf ( "Hello!\n" );
        {
                int j;
                printf ( "Hi!\n" );
        };
};

I always thought that extra sets of braces (without starting a new function
or a for, while, etc.) were illegal in ANSI C AND that declaring variables
after the start of code like this (unless beginning a new function) was
illegal. I thought those things were only allowed in C++. HOWEVER, Turbo
C++ compiles it fine EVEN with the C++ functionality turned off (should
make it a regular C compiler).

Can someone please set me straight?

Thanks,

Sean


At 01:45 PM 6/7/99 -0400, you wrote:
>For automatic variables, no, but static duration variables, yes.
>
>ANS X3.159-1989 3.5.7 Initialization
>        "If an object that has automatic storage duration is not initialized
>explicitly, its value is indeterminate. If an object that has static
>storage duration is not initialized explicitly, it is initialized
>implicitly as if every member that has arithmetic type were assigned 0 and
>every member that has pointer type were assigned a null pointer constant."
>
>It is not unreasonable, IMO, for compilers for small processors to, at
>least optionally, waive the implicit initialization of static duration
>objects, as it's good style to explicitly initialize any variable upon
>whose startup-value the program will depend and initializing a bunch of
>locations to zero when it's not necessary can chew up a lot of cycles at
>startup that could be put to better use.
>
>        Jim
>
>James Grosbach
>Development Systems
>Microchip Technology
>james.grosbach@microchip.com
>
|
| Sean Breheny
| Amateur Radio Callsign: KA3YXM
| Electrical Engineering Student
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