where is the memory corruption?

[ag0aep6g]

On 09.12.20 21:35, Jack wrote:
> I'm on linux/opensuse, trying to pass a wchar_* from C to D but I'm 
> getting only the first letter of that string. Could someone help figure 
> out why?
> 
> this is the piece of D code:
> 
> extern(C) export
> void sayHello(const (wchar) *s)
[...]
> and below the piece of C code where I call the lib's function, compiled 
> with clang -std=c11 -m64 dll.c -ldl
[...]
>    const wchar_t *s2 = L"hello!";
>    void (*fp)(const wchar_t*) = dlsym(lh, "sayHello");
>    char *de = dlerror();
>    if(de) {
>      fprintf(stderr, "slsym error:%s\n", de);
>      return EXIT_FAILURE;
>    }
>    fp(s2);
> 
> the output is "h" rather "hello". What am I missing?

D's wchar is not C's wchar_t. D's wchar is 16 bits wide. The width of 
C's wchar_t is implementation-defined. In your case it's probably 32 bits.

Because of that size mismatch, sayHello sees your L"hello!" string as 
"h\0e\0l\0l\0o\0!\0"w. And the conversion correctly stops at the first 
null character.

My C isn't very good, but I think char_16t is the correct analog to D's 
wchar. https://en.cppreference.com/w/c/string/multibyte/char16_t