On Wednesday, 15 August 2018 at 02:40:22 UTC, Joe wrote:
I understand that, Mike. However if I'm not mistaken given
something in C like
char* strs[] = { "This", "is a", "test"};
AFAIK, even with -betterC and an extern (C), the literals will
still be understood by D as type "string", and there is no
other way around it, right?
I could put the array and the function in its own C file for
the time being, but instead chose to replace the toStringz by a
small hack: use memcpy to copy the string to a stack fixed, big
enough array and a NUL terminator.
String literals are implicitly convertible to const(char)* and
are guaranteed to be nul-terminated like a C string, so this
works:
import core.stdc.stdio;
extern(C) void main()
{
const(char)* foo = "foo";
puts(foo);
}
https://run.dlang.io/is/FZSXc3
For plain char*, a simple cast works:
char* foo = cast(char*)"foo";
The problem is with the array initializer, as the C-style {x, y,
z} only works on structs in D, and D's [x, y, z] requires
TypeInfo, which isn't available in -betterC, a problem you run
into even when your array is string[].
However, the initializer works fine with static arrays in
-betterC, so this works:
import core.stdc.stdio;
extern(C):
void some_c_func(const char** strs, size_t numStrs) {
for(size_t i=0; i<numStrs; ++i) {
puts(strs[i]);
}
}
void main()
{
const(char)*[3] strs = ["one", "two", "three"];
some_c_func(strs.ptr, strs.length);
}
https://run.dlang.io/is/pxmGyh
Does that help?
