C file cannot be compiled in c++ Visual Studio - c++

Question

For some reason I can no longer compile a c file in my c++ clr console application. It worked before without the clr support, I also switched my project to compile as /TP still not working. Any help would be greatly appreciated.
Error
Severity Code Description Project File Line Suppression State
Error C2664 'int strcmp(const char *,const char *)': cannot convert argument 1 from 'WCHAR [260]' to 'const char *'
snowkill.c
#include "snowkill.h"
void killProcessByName(WCHAR *filename)
{
HANDLE hSnapShot = CreateToolhelp32Snapshot(TH32CS_SNAPALL, NULL);
PROCESSENTRY32 pEntry;
pEntry.dwSize = sizeof(pEntry);
BOOL hRes = Process32First(hSnapShot, &pEntry);
while (hRes)
{
if (strcmp(pEntry.szExeFile, filename) == 0)
{
HANDLE hProcess = OpenProcess(PROCESS_TERMINATE, 0,
(DWORD)pEntry.th32ProcessID);
if (hProcess != NULL && pEntry.th32ProcessID != GetCurrentProcessId())
{
TerminateProcess(hProcess, 9);
CloseHandle(hProcess);
}
}
hRes = Process32Next(hSnapShot, &pEntry);
}
CloseHandle(hSnapShot);
}
snowkill.h
#pragma once
#include "stdafx.h"
#include <windows.h>
#include <process.h>
#include <Tlhelp32.h>
#include <winbase.h>
#include <string.h>
#ifdef __cplusplus
extern "C" {
#endif
void killProcessByName(WCHAR *filename);
#ifdef __cplusplus
}
#endif
main.cpp
#include "stdafx.h"
#include "snowkill.h"
#include "motion.h"
#include "info.h"
#include "flushsound.h"
#include "snowserial.h"
using namespace System;
bool on() {
return true;
}
bool off() {
return false;
}
int main()
{
listenoncommport();
for (;;) {
string onoff = checkfile();
if (onoff == "1")
{
//detected();
}
else
{
WCHAR *proccc = L"firefox.exe";
killProcessByName(proccc);
//notdetected();
}
Sleep(5000);
}
return 0;
}

Answer 1

You could change every instance of WCHAR to TCHAR so text setting is "generic", or as already mentioned, change the project property character set to be Unicode only.
void killProcessByName(TCHAR *filename)
/* ... */
if (_tcscmp(pEntry.szExeFile, filename) == 0) /* replaced strcmp */
/* ... */
#include <windows.h> /* needed in order to use TEXT() macro */
/* ... */
TCHAR *proccc = TEXT("firefox.exe"); /* TEXT() is a <windows.h> macro */
Use TCHAR type everywhere if the functions involved are not WCHAR specific. That would allow project setting to build either ANSI/ASCII (not set) or Unicode.
Note that Process32First and Process32Next use TCHAR.
This is mostly for legacy, since Windows 2000 and later API functions use Unicode internally, converting ANSI/ASCII to Unicode as needed, while Windows NT and older API functions use ANSI/ASCII.
However, typically many or most text files (such as source code) are ANSI/ASCII and not Unicode, and it's awkward to have to support Unicode for Windows API and then ANSI/ASCII for text files in the same program, and for those projects I use ANSI/ASCII.
By using the TCHAR based generic types, I can share common code with projects that use Unicode and with projects that use ANSI/ASCII.

Answer 2

The error message is clear: you have an error at this precise line:
if (strcmp(pEntry.szExeFile, filename) == 0)
Because your arguments are not of char* type as expected by strcmp but WCHAR* types. You should use wcscmp instead, which is basically the same function, but working with wchar_t* type.

Answer 3

szExeFile in tagPROCESSENTRY32 is declared as TCHAR, which will be a 1-byte char when compiling with Character Set set to 'Not Set' or 'Multibyte'. Set Character Set in your project settings to Use Unicode Character Set to fix the problem.
Also, use wcscmp to compare WCHAR types.