is this a bug ? mixin template static function missing!
#!/usr/bin/env rdmd
import core.stdc.stdio;
template G(size_t line = __LINE__, A...){
int i = 3;
static extern(C) pragma(crt_constructor) void init2(){
printf("init: %d\n", line);
}
}
pragma(crt_constructor) extern(C) void init1(){
printf("init from global\n");
}
struct A {
mixin G!();
}
extern(C) void main(){
mixin G!() g;
printf("g.i=%d\n", g.i);
g.init2(); // remove this can build, but g.init2 not get called!
}
-
build error:
Undefined symbols for architecture x86_64:
"__D4test4mainUZ1g5init2UNbNiZv", referenced from:
Re: is this a bug ? mixin template static function missing!
On Friday, 10 August 2018 at 08:31:21 UTC, learnfirst1 wrote:
#!/usr/bin/env rdmd
import core.stdc.stdio;
template G(size_t line = __LINE__, A...){
int i = 3;
static extern(C) pragma(crt_constructor) void init2(){
printf("init: %d\n", line);
}
}
pragma(crt_constructor) extern(C) void init1(){
printf("init from global\n");
}
struct A {
mixin G!();
}
extern(C) void main(){
mixin G!() g;
printf("g.i=%d\n", g.i);
g.init2(); // remove this can build, but g.init2 not get
called!
}
-
build error:
Undefined symbols for architecture x86_64:
"__D4test4mainUZ1g5init2UNbNiZv", referenced from:
It is indeed. Reduced example:
template G(){
extern(C) pragma(crt_constructor) void init(){}
}
void main(){
mixin G!();
init();
}
For nested functions, extern(C) is simply ignored[0]. Since
pragma(crt_constructor) requires that the symbol it's applied to
uses C linkage (and an error message to that effect is shown if
you write pragma(crt_constructor) void fun() {} in module scope:
Error: function `fun` must be extern(C) for
pragma(crt_constructor)
In addition, if you try to apply pragma(crt_constructor) to a
nested function, you get this error message, showing further that
nested functions can't be crt_constructors:
Error: unrecognized pragma(crt_constructor)
The correct behavior would be for the compiler to show the latter
error message for a mixin'd function as well.
Filed a bug:
https://issues.dlang.org/show_bug.cgi?id=19153
--
Simen
[0]: from https://dlang.org/spec/attribute.html#linkage:
Note that extern(C) can be provided for all types of
declarations, including struct or class, even though there is no
corresponding match on the C side. In that case, the attribute is
ignored. This behavior applies for nested functions and nested
variables as well.
Re: is this a bug ? mixin template static function missing!
On Friday, 10 August 2018 at 10:24:55 UTC, Simen Kjærås wrote:
On Friday, 10 August 2018 at 08:31:21 UTC, learnfirst1 wrote:
The correct behavior would be for the compiler to show the
latter error message for a mixin'd function as well.
Filed a bug:
https://issues.dlang.org/show_bug.cgi?id=19153
--
Simen
I think the static extern(C) nested function should just work
like global extern(C) function. DMD still report missing
symbols. Or I am wrong about this ?
template G(){
static extern(C) pragma(crt_constructor) void init(){}
}
void main(){
mixin G!(); // Line 5
init();
}
Re: is this a bug ? mixin template static function missing!
On Friday, 10 August 2018 at 10:24:55 UTC, Simen Kjærås wrote:
On Friday, 10 August 2018 at 08:31:21 UTC, learnfirst1 wrote:
Filed a bug:
https://issues.dlang.org/show_bug.cgi?id=19153
template G(){
pragma(crt_constructor) static extern(C) void init(){}
}
void main(){
mixin G!(); // Line 5
init();
}
same missing symbols.
Re: is this a bug ? mixin template static function missing!
On Friday, 10 August 2018 at 11:17:10 UTC, learnfirst1 wrote:
I think the static extern(C) nested function should just work
like global extern(C) function. DMD still report missing
symbols. Or I am wrong about this ?
template G(){
static extern(C) pragma(crt_constructor) void init(){}
}
void main(){
mixin G!(); // Line 5
init();
}
If you try the same without the mixin template, you'll see that
it doesn't work:
void main() {
static extern(C) pragma(crt_constructor) void init();
init();
}
Depending on the order of static, extern(C) and
pragma(crt_constructor), you can get at least two different error
messages, but either way - it doesn't work.
It would be possible to make this work by changing the compiler,
but according to spec, it shouldn't.
--
Simen
Re: is this a bug ? mixin template static function missing!
On Friday, 10 August 2018 at 12:05:52 UTC, Simen Kjærås wrote:
On Friday, 10 August 2018 at 11:17:10 UTC, learnfirst1 wrote:
If you try the same without the mixin template, you'll see that
it doesn't work:
struct Test {
extern(C) pragma(crt_constructor) static void init(){ // work
int i = 3;
}
}
void main(){
extern(C) pragma(crt_constructor) static void init(){ // not
work
int i = 3;
}
}
--
It not work make no sense, since it can work on struct.
I am not be able to search the related spec docs, only this
link:
https://dlang.org/blog/2018/01/04/dmd-2-078-0-has-been-released/
Based on my understand, nested static extern(C) function is all
about visibility. It just like put private before it, there is
really no reason to treat them in diff way.
