In C/C++, the linker will refuse to include a translation unit if there's no call from another translation unit that's already been accepted into the executable.

Can the same thing occur in D?  I know this is an obscure kind of problem.  Here's some code that could be affected by this kind of issue.

import myRegistrationMechanism.register

static this(){
  register(functionNotUsedAnywhereElse);
}

void functionNotUsedAnywhereElse(inout int x){
  x += 17;
}

Jason House Wrote:

> In C/C++, the linker will refuse to include a translation unit if there's no call from another translation unit that's already been accepted into the executable.
> 
> Can the same thing occur in D?  I know this is an obscure kind of problem.  Here's some code that could be affected by this kind of issue.
> 
> import myRegistrationMechanism.register
> 
> static this(){
>    register(functionNotUsedAnywhereElse);
> }
> 
> void functionNotUsedAnywhereElse(inout int x){
>    x += 17;
> }

If I remember correctly, OPTLINK (the linker DMD uses under Windows) does this, and gnu link has an option to do it.

Now, using the gnu link option (--gc-sections, I think) *does* cause problems.  However, OPTLINK doesn't.

Also, with that example, all the functions *do* get called.  Specifically, static this() gets called by the _moduleCtor function, which I believe is generated by the compiler at compile time.

So, long and short of it: yes. :)

        -- Daniel

Daniel Keep schrieb am 2007-03-26:
> Jason House Wrote:
>
>> In C/C++, the linker will refuse to include a translation unit if there's no call from another translation unit that's already been accepted into the executable.
>> 
>> Can the same thing occur in D?  I know this is an obscure kind of problem.  Here's some code that could be affected by this kind of issue.
>> 
>> import myRegistrationMechanism.register
>> 
>> static this(){
>>    register(functionNotUsedAnywhereElse);
>> }
>> 
>> void functionNotUsedAnywhereElse(inout int x){
>>    x += 17;
>> }
>
> If I remember correctly, OPTLINK (the linker DMD uses under Windows) does this, and gnu link has an option to do it.
>
> Now, using the gnu link option (--gc-sections, I think) *does* cause problems. However, OPTLINK doesn't.

That isn't due to the linker used but how DMD generates the exception handling code: http://d.puremagic.com/issues/show_bug.cgi?id=879

Thomas