错误C2664：'errno_t wcstombs_s（size_t *，char *，size_t，const wchar_t *，size_t）'：无法转换参数4

Question

error C2664: 'errno_t wcstombs_s(size_t *,char *,size_t,const wchar_t *,size_t)' : cannot convert parameter 4 from 'CHAR [260]' to 'const wchar_t *' 1>
Types pointed to are unrelated; conversion requires reinterpret_cast, C-style cast or function-style cast

What does this error mean?

As my function is:

BOOL DependentDLLDisplay()
{
    char arr[200];

    if(!Module32First(hProcessSnap,&me32))
    {
        cout<<" ERROR : Failed to Get DLL Information"<<endl;
        CloseHandle(hProcessSnap);
        return FALSE;
    }

    cout<<endl<<"DEPENDENT DLL OF THIS PROCESS :"<<endl;
    do
    {
        wcstombs_s(NULL,arr,200,me32.szModule,200);
        cout<<arr<<endl;
    }while(Module32Next(hProcessSnap,&me32));

    CloseHandle(hProcessSnap);
    return TRUE;
}

Answer 1

Your object me32 is of the type MODULEENTRY32 as defined here:

https://msdn.microsoft.com/en-us/library/windows/desktop/ms684225.aspx

The szModule field that you pass as the 4th parameter to 'wcstombs_s` is defined as:

TCHAR   szModule[MAX_MODULE_NAME32 + 1];

In the Windows API, TCHAR is defined as char in MBCS encoding, and wchar in UNICODE encoding.

The error you are seeing is indicating that you are including the MBCS version of the Windows library, thus MODULEENTRY32 is actually MODULEENTRY32A and me32.szModule is a char[] , but are then trying to treat me32.szModule as if it were a wide wchar_t[] string when it is in fact an Ansi char[] string.

You can either switch to the UNICODE libraries by changing your project settings, or using a normal char string copy to obtain the value of that field.

Or, as Remy stated:

Or, you can explicitly use Module32FirstW() / Module32NextW() , MODULEENTRY32W , std::wcout , etc, or explicitly use Module32FirstA() / Module32NextA() , MODULEENTRY32A , etc. Either way, you do not have to change the project settings. Don't use TCHAR -based APIs anymore. In this case, since the code wants to end up with a char[] string, it makes sense to use Module32FirstA() / Module32NextA() and just remove wcstombs_s() altogether.

One last note: You should probably expand your local variable to be the same size of szModule rather than potentially truncate the contents.