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digitalmars.D.learn - Why free and realloc seem to include .

reply Michael <michael toohuman.io> writes:
So this might be a bit of a stupid question, but looking at the 
DMD source code (dmodule.d in particular) I see the following 
code:


if (srcfile._ref == 0)
    .free(srcfile.buffer);
srcfile.buffer = null;
srcfile.len = 0;


and I was just wondering why certain functions seem to be called 
using the dot operator on its own, unattached to some object. 
This is probably a naive question but I haven't seen this in my 
limited experience using D and I was just wondering why this is. 
I have only really seen this relating to D's manual memory 
management. But in the same file, I see examples like this:


FileName.free(n);


so what is the case when you should use .free() and why not just 
free()? Thanks.
Aug 03 2017
parent reply Temtaime <temtaime gmail.com> writes:
On Thursday, 3 August 2017 at 14:03:56 UTC, Michael wrote:

 So this might be a bit of a stupid question, but looking at the 
 DMD source code (dmodule.d in particular) I see the following 
 code:


if (srcfile._ref == 0)
    .free(srcfile.buffer);
srcfile.buffer = null;
srcfile.len = 0;


 and I was just wondering why certain functions seem to be 
 called using the dot operator on its own, unattached to some 
 object. This is probably a naive question but I haven't seen 
 this in my limited experience using D and I was just wondering 
 why this is. I have only really seen this relating to D's 
 manual memory management. But in the same file, I see examples 
 like this:


FileName.free(n);


 so what is the case when you should use .free() and why not 
 just free()? Thanks.


Dot is equal to C++'s :: operator to access a global namespace.
Aka ::free(ptr);
Aug 03 2017
parent reply Michael <michael toohuman.io> writes:
On Thursday, 3 August 2017 at 14:15:40 UTC, Temtaime wrote:

 On Thursday, 3 August 2017 at 14:03:56 UTC, Michael wrote:

 So this might be a bit of a stupid question, but looking at 
 the DMD source code (dmodule.d in particular) I see the 
 following code:


[...]


 and I was just wondering why certain functions seem to be 
 called using the dot operator on its own, unattached to some 
 object. This is probably a naive question but I haven't seen 
 this in my limited experience using D and I was just wondering 
 why this is. I have only really seen this relating to D's 
 manual memory management. But in the same file, I see examples 
 like this:


[...]


 so what is the case when you should use .free() and why not 
 just free()? Thanks.


 Dot is equal to C++'s :: operator to access a global namespace.
 Aka ::free(ptr);


I've not seen that either, though I'm not a C++ programmer. Does 
using free() on its own not assume access of a global namespace?
Aug 03 2017
parent reply Adam D. Ruppe <destructionator gmail.com> writes:
On Thursday, 3 August 2017 at 15:18:17 UTC, Michael wrote:

 I've not seen that either, though I'm not a C++ programmer. 
 Does using free() on its own not assume access of a global 
 namespace?


Consider the following:

class Foo {
    void free(void*);

    void other_method() {
       free(ptr); // calls the member function
    }
}


The leading dot in D just ensures it calls the global one instead 
of a member (if present).
Aug 03 2017
parent Michael <michael toohuman.io> writes:
On Thursday, 3 August 2017 at 15:29:29 UTC, Adam D. Ruppe wrote:

 On Thursday, 3 August 2017 at 15:18:17 UTC, Michael wrote:

 I've not seen that either, though I'm not a C++ programmer. 
 Does using free() on its own not assume access of a global 
 namespace?


 Consider the following:

 class Foo {
    void free(void*);

    void other_method() {
       free(ptr); // calls the member function
    }
 }


 The leading dot in D just ensures it calls the global one 
 instead of a member (if present).


So it could be used without, but you risk conflicts with other 
functions. I got it, thanks to both of you.
Aug 03 2017