Re: Programming Windows D Examples are now Online!

[Walter Bright]

On 6/21/2011 12:35 PM, Andrej Mitrovic wrote:
Float/Doubles are initialized to NaN in D, however I don't know what
they're initialized to in C.

In C they're initialized to 0 for globals, and garbage for locals and allocated 
data.


A big issue with porting is that D's character arrays are always
initialized to invalid values. This wreaks havoc in code, in
particular with static arrays. For example:

     char[100] buffer;
     APIWriteToBuffer(buffer.ptr);
     myDStringFunction(buffer[]);  //<- buggy code

In C buffer is not initialized to 0, if it is not global, it is initialized to 
garbage.

The problem is twofold. First, the API call might not work because it
could easily expect a null terminator to be present as a first
character:
     char[100] buffer;
     APIWriteToBuffer(buffer.ptr);  // Might not work!

Fix:

       char[100] buffer = 0;

So when you finally call a D function with such a static array, it
could print out garbage or throw an exception:
     char[100] buffer;
     APIWriteToBuffer(buffer.ptr);
     myDStringFunction(buffer[]);  // what will this function do when
stumbles on '\0' or char.init?

Fix:
        char[100] buffer;
        APIWriteToBuffer(buffer.ptr);
        auto p = buffer[0 .. strlen(buffer.ptr)];
        myDStringFunction(p);