On Thursday, 7 April 2022 at 12:51:26 UTC, Stanislav Blinov wrote:
On Thursday, 7 April 2022 at 10:50:35 UTC, BoQsc wrote:
wchar_t* clang_string = cast(wchar_t *)"AAAAAAAAAA";
You're witnessing undefined behavior. "AAAAAAAAAA" is a string
literal and is stored in the data segment. Mere cast to
wchar_t* does not make writing through that pointer legal.
Moreover, even if it was legal to write through it, that alone
wouldn't be sufficient. From documentation of `wcsncat`:
The behavior is undefined if the destination array is not
large enough for the contents of both str and dest and the
terminating null wide character.
`wcsncat` does not allocate memory, it expects you to provide a
sufficiently large mutable buffer. For example, like this:
```d
// ...
auto cls = new wchar_t[256];
cls[] = 0;
cls[0..10] = 'A';
wchar_t* clang_string = cls.ptr;
// ...
```
That is correct, the results are satisfying. I believe this
thread is resolved.
```
import std.stdio;
@system void main(){
import std.utf : toUTF16z, toUTF16;
import core.stdc.wchar_ : wcsncat, wcslen, wprintf;
import core.stdc.stdlib : wchar_t;
import core.sys.windows.winnt : LPCWSTR;
auto cls = new wchar_t[256];
cls[] = 0;
cls[0..10] = 'A';
wchar_t* clang_string = cls.ptr;
//wchar_t* clang_string = cast(wchar_t *)"AAAAAAAAAA";
wstring dlang_string = "BBBBBBBBBB"w; //<---- NEW,
same results
LPCWSTR winpointer_to_string = "CCCCCCCCCC";
wcsncat(clang_string, dlang_string.toUTF16z,
wcslen(dlang_string.toUTF16z));
// String output: AAAAAAAAAABBBBBBBBBB
wcsncat(clang_string, winpointer_to_string,
wcslen(winpointer_to_string));
// String output: AAAAAAAAAABBBBBBBBBBCCCCCCCCCC
// Expected string: AAAAAAAAAABBBBBBBBBBCCCCCCCCCC
wprintf(clang_string);
// String output: AAAAAAAAAABBBBBBBBBBCCCCCCCCCC
// Expected string: AAAAAAAAAABBBBBBBBBBCCCCCCCCCC
}
```
