On 2015-12-11 09:51, Mike McKee wrote:
So I'm having trouble figuring out the D and C code.
Created dfunc.d with this:
extern (C) string dfunc(string s) {
return s ~ "response";
}
Then compiled:
$ dmd -c dfunc.d
This created dfunc.o without error.
Next, I created C code like so:
extern char * dfunc(char *);
char * c_dfunc(char *s) {
return dfunc(s);
}
"string" in D is not the same as "char*" in C. "string" is an alias to
an array of immutable characters. An array in D consists of the length
of the array and a pointer to the data.
The interface of the function needs to only contain C types. Something
like this:
extern (C) char* dfunc(char* s);
If you want to use the D string operations, like ~, you need to convert
it to a D string, do the concatenation, and then convert it back to a C
string [2] [3].
See [3] for more information.
[1] http://dlang.org/phobos/std_string.html#.toStringz
[2] http://dlang.org/phobos/std_string.html#.fromStringz
[3] http://dlang.org/spec/interfaceToC.html
--
/Jacob Carlborg
