Question re specific implicit type coercion

Don Allen donaldcallen at
Mon Oct 18 15:04:11 UTC 2021

I am calling a C function, described in D as

extern (C) GtkWidget* gtk_menu_item_new_with_label 

I call it like this

accounts_menu_item = gtk_menu_item_new_with_label("New account 

The type of the string literal in the call is immutable(char)[]. 
The type of the parameter is a pointer to immutable characters.

This setup works.

My question is about the documentation vs. what is really going 
on here.

Section 12.17 of the Language Reference does not indicate any 
circumstance in which a dynamic array, which the literal is, is 
implicitly coerced to a pointer. I realize that this is a special 
case -- the callee is a C function -- that might not be covered 
by this section. So I looked at Section 32.3, Chapter 32 being 
"Interfacing to C". 32.3 contains a table of correspondences 
between D and C types. The entry for the D type T[] indicates no 
correspondence in C.

So at least my reading of the documentation suggests that my code 
should not compile. And yet it does and works, which leads me to 
believe there is a documentation error that ought to be reported.

Before doing so, I decided to send this message so those of you 
who know D a lot better than I do can tell me what I've missed or 
gotten wrong, if that is the case.

Thanks --

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