Re: Struggling with wchar[] to string conversion

[Jack via Digitalmars-d-learn]

On Tuesday, 19 January 2021 at 15:32:12 UTC, Stefan wrote:
Hi,
I am using dmd2.081.1 on windows building a 32 bit executable.

I am trying to find out how many instances of the same program 
are running. Therefor I use the core.sys.windows.tlhelp32 
module.

With the CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0) and 
Process32First/Process32Next I iterate over all processes and 
for each process I iterate with 
CreateToolhelp32Snapshot(TH32CS_SNAPMODULE, dwPID) and 
Module32First/Module32Next over all modules of a process.
The Model32First/..Next fill a MODULEENTRY32 structure which 
contains a szExePath member that is a wchar[260].
Converting this to a string succeeds (compiler does not 
complain) with
me32.szExePath.text
However, comparing this with the result of thisExePath() 
(std.file) never succeeds although the two string values when 
written with writeln() appear to be the same.

This drives me crazy!

Any ideas?

Tschüß,
Stefan

How are you trying to do such version? if member is of wchar[] 
get the .ptr and so that you have the memory pointer to operate 
with

import std.stdio;
import core.stdc.stddef : wchar_t;
import core.sys.windows.windows;

void main()
{
    wchar[MAX_PATH] buffer;
    GetModuleFileName(NULL, buffer.ptr, MAX_PATH);
    auto s = LPWSTRToDString(buffer.ptr);
    writeln(s);
}

// try-catch so that we can mark it as nothrow
string LPWSTRToDString(T)(T s) nothrow
if(is(T == LPWSTR) || is(T == wchar_t*) || is(T == const(wchar)*))
{
    import std.conv : to;
    import std.string : fromStringz;

    try {
          return to!(string)(s.fromStringz);
   } catch(Exception e) { // do your error-handling here
           return "";
   }
}