Is D's GC.calloc and C's memset played the same role?

[Daniel Kozak via Digitalmars-d-learn]

FrankLike via Digitalmars-d-learn píše v Út 23. 12. 2014 v 15:37 +0000:
> Today,I meet a question:get all processes names.
> 
> ----------C++ CODE-----------------
> #include "stdafx.h"
> #include <windows.h>
> #include <stdio.h>    //C standard I/O
> #include <tlhelp32.h>
> 
> int _tmain(int argc, _TCHAR* argv[])
> {
>      HANDLE 
> hProcessSnap=CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS,0);
> 
>      if(hProcessSnap==INVALID_HANDLE_VALUE)
>      {
>          _tprintf(_T("CreateToolhelp32Snapshot error!\n"));
>          return -1;
>      }
> 
>      PROCESSENTRY32 pe32;
>      pe32.dwSize = sizeof(PROCESSENTRY32);
> 
>      BOOL bMore=Process32First(hProcessSnap,&pe32);
>      int i=0;
> 
>      _tprintf(_T("PID\t thread nums \t name \n"));
> 
>      while(bMore)
>      {
>          bMore=Process32Next(hProcessSnap,&pe32);
>          _tprintf(_T("%u\t"),pe32.th32ProcessID);
>          _tprintf(_T("%u\t"),pe32.cntThreads);
>          _tprintf(_T("%s\n"),pe32.szExeFile);
> 
>          i++;
>      }
> 
>      CloseHandle(hProcessSnap);
>      _tprintf(_T("Count:%d\n"),i);
> 
>      return 0;
> }
> ----------------D code--------------------------
> import std.stdio;
> import std.string;
> import core.sys.windows.windows;
> import core.memory;
> import win32.tlhelp32;
> 
> void main()
> {
>   	
>      HANDLE 
> hProcessSnap=CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS,0);
> 
>      if(hProcessSnap is null)
>      {
>          writeln("CreateToolhelp32Snapshot error!\n");
>          return ;
>      }
> 
>      PROCESSENTRY32* pe32 = 
> cast(PROCESSENTRY32*)GC.calloc(PROCESSENTRY32.sizeof);
> 
>       pe32.dwSize = PROCESSENTRY32.sizeof;
> 
>      bool bMore=cast(bool)Process32First(hProcessSnap,pe32);
>      int i=0;
> 
>      writeln("PID\t thread nums\t name \n");
> 
>      while(bMore)
>      {
>          bMore=cast(bool)Process32Next(hProcessSnap,pe32);
>         string s = cast(string)pe32.szExeFile;
>         auto a = s.indexOf('\0');
>         if(a >=0)
>          
> writeln("\t",pe32.th32ProcessID,"\t",pe32.cntThreads,"\t",s[0..a]);
>          i++;
>      }
> 
>      CloseHandle(hProcessSnap);
>      writeln(format("count:%d",i));
> 
>      return ;
> }
> -----------------------end----------------------
> you will find the different:
>   D: PROCESSENTRY32* pe32 = 
> cast(PROCESSENTRY32*)GC.calloc(PROCESSENTRY32.sizeof);
> 
> C++:PROCESSENTRY32 pe32;
> 
> GC.calloc means: memset ?!
calloc means alloc cleared memory same as malloc but clear all bits to
zero