Is it possible to prevent system() from stealing focus? [duplicate] - c++

I am coding a C program in Dev-C++, and I need to use a couple of Windows (CMD) commands. It is easy, but when the command in the system() function is executed, the program runs the console in the execution.
An example:
#include <stdio.h>
#include <stdlib.h>
#include <windows.h>
int main()
{
system("if not exist c:\my_docs\doc.txt (xcopy /Y doc.txt c:\my_docs\)"); // Cmd command
system("pause");
return 0;
}
Exists other function, or a modification that do not shows the console?
Thanks you! Best regards.

You can use WinExec("your cmd command", SW_HIDE); instead of system("cmd command").

You can do it with CreateProcess.
STARTUPINFOW si;
PROCESS_INFORMATION pi;
ZeroMemory(&si, sizeof(si));
si.cb = sizeof(si);
ZeroMemory(&pi, sizeof(pi));
if (CreateProcessW(command, arg, NULL, NULL, FALSE, CREATE_NO_WINDOW, NULL, NULL, &si, &pi))
{
WaitForSingleObject(pi.hProcess, INFINITE);
CloseHandle(pi.hProcess);
CloseHandle(pi.hThread);
}

As FigBug stated, CreateProcess() is the way to go, but I don't think that CreateProcess() can execute a shell if statement. You may need to pass it something like this as a command:
"cmd.exe /c \"if not exist c:\my_docs\doc.txt (xcopy /Y doc.txt c:\my_docs\)\""
But a better solution might be to use CreateFile() to test if a file exists and CopyFile() to copy it.

NOTE: My answer is not necessarily tailored to your specific question, but this Q&A is the top Google result for "Windows system without command prompt" and other similar queries.
Here's a way to execute commands without a new cmd.exe window. Based on Roland Rabien's answer and MSDN, I've written a working function.
#include "AtlBase.h"
#include "AtlConv.h"
int windows_system(const char *cmd) {
PROCESS_INFORMATION p_info;
STARTUPINFO s_info;
DWORD ReturnValue;
CA2T programpath(cmd);
memset(&s_info, 0, sizeof(s_info));
memset(&p_info, 0, sizeof(p_info));
s_info.cb = sizeof(s_info);
if (CreateProcess(programpath, NULL, NULL, NULL, 0, 0, NULL, NULL, &s_info, &p_info)) {
WaitForSingleObject(p_info.hProcess, INFINITE);
GetExitCodeProcess(p_info.hProcess, &ReturnValue);
CloseHandle(p_info.hProcess);
CloseHandle(p_info.hThread);
}
return ReturnValue;
}
Works on all Windows platforms. Call just like you would system().

int win_system(const char *command)
{
// Windows has a system() function which works, but it opens a command prompt window.
char *tmp_command, *cmd_exe_path;
int ret_val;
size_t len;
PROCESS_INFORMATION process_info = {0};
STARTUPINFOA startup_info = {0};
len = strlen(command);
tmp_command = malloc(len + 4);
tmp_command[0] = 0x2F; // '/'
tmp_command[1] = 0x63; // 'c'
tmp_command[2] = 0x20; // <space>;
memcpy(tmp_command + 3, command, len + 1);
startup_info.cb = sizeof(STARTUPINFOA);
cmd_exe_path = getenv("COMSPEC");
_flushall(); // required for Windows system() calls, probably a good idea here too
if (CreateProcessA(cmd_exe_path, tmp_command, NULL, NULL, 0, CREATE_NO_WINDOW, NULL, NULL, &startup_info, &process_info)) {
WaitForSingleObject(process_info.hProcess, INFINITE);
GetExitCodeProcess(process_info.hProcess, &ret_val);
CloseHandle(process_info.hProcess);
CloseHandle(process_info.hThread);
}
free((void *) tmp_command);
return(ret_val);
}

Related

How to run a Videofile using VLC player Using C++

#include<Windows.h>
#include<direct.h>
int main()
{
_chdir`("C:\\Program Files (x86)\\VideoLAN\\VLC");
system("vlc C:\\Users\\Documents\\Wildlife.wmv");
return 0;
}
By using the above code i am successfully able to run the video using vlc player but as the video finishes,still the VLC player window doesn't get close.How to shut the VLC player window?
Please post your valuable suggestion
Use option --play-and-exit or vlc://quit, namely
system("vlc file:///C:\\Users\\Documents\\Wildlife.wmv --play-and-exit");
or
system("vlc file:///C:\\Users\\Documents\\Wildlife.wmv --vlc://quit");
If you want to use another system call to terminate it, try this on Windows:
system("taskkill /im vlc.exe");
Use CreateProcess to pass the correct commandline. See the example below. Note the use of \" separators.
#include <Windows.h>
int main()
{
const char *appname = "c:\\Program Files (x86)\\VideoLAN\\VLC\\vlc.exe";
const char *filename = "c:\\files\\my file.wav";
STARTUPINFOA si;
PROCESS_INFORMATION pi;
memset(&si, 0, sizeof(si));
si.cb = sizeof(si);
memset(&pi, 0, sizeof(pi));
char buf[MAX_PATH + 300];
wsprintfA(buf, "%s \"%s\" --play-and-exit", appname, filename);
CreateProcessA(0, buf, NULL, NULL, FALSE, 0, NULL, NULL, &si, &pi);
return 0;
}
Use Unicode if that's a proper Windows program.
You need to:
Get all process IDs running at that time using EnumProcesses():https://msdn.microsoft.com/en-us/library/windows/desktop/ms682629(v=vs.85).aspx
Call OpenProcess() on each process in that above list and get a HANDLE:http://msdn.microsoft.com/en-us/library/windows/desktop/ms684320(v=vs.85).aspx
If you managed to get a HANDLE call GetModuleBaseName() and get the process name:http://msdn.microsoft.com/en-us/library/windows/desktop/ms683196(v=VS.85).aspx
Check the name and if you have found your target process in this case "vlc", call TerminateProcess():http://msdn.microsoft.com/en-us/library/windows/desktop/ms686714(v=VS.85).aspx
This is just a way...

trying to run commend on cmd throw c++ using createprocces (API)?

bool execute()
{
STARTUPINFO si;
PROCESS_INFORMATION pi;
bool flag = true;
ZeroMemory(&si, sizeof(si));
si.cb = sizeof(si);
ZeroMemory(&pi, sizeof(pi));
string f = "dir desktop"
if (CmdLine.parameter != "")
{
LPSTR l1 = const_cast<char *>(f.c_str());
CreateProcess(NULL, l1, NULL, NULL, false, 0, NULL, NULL, &si, &pi);
flag = true;
// WaitForSingleObject(pi.hProcess, INFINITE);
// // Close process and thread handles.
// CloseHandle(pi.hProcess);
// CloseHandle(pi.hThread);
//}
}
return flag;
}
I'm trying to run cmd command by visual studio.
I'm using createprocces (API) in order to run this thing
but I can't understand why it doesn't run anything.
dir is a command understood by cmd.exe, it's not a program you can execute.
You can try the command cmd /k "dir desktop", properly expressed as a C++ string.
E.g.,
auto execute()
-> bool
{
STARTUPINFO si = { sizeof( si ) };
PROCESS_INFORMATION pi = {};
string f = "cmd /k \"dir desktop\"\0";
bool const ok = !!CreateProcess( 0, &f[0], 0, 0, false, 0, 0, 0, &si, &pi );
if( !ok ) { return false; }
WaitForSingleObject(pi.hProcess, INFINITE);
CloseHandle(pi.hProcess);
CloseHandle(pi.hThread);
return true;
}
Note how the calls to ZeroMemory have been replaced with C++ initialization.
Just by letting the compiler do its job you get shorter, more clear code that is more likely correct, and just as efficient (possibly more). Win win win.
Disclaimer: code not reviewed by compiler.
If the intent is to list the contents of the user's desktop folder, then note that dir desktop doesn't do that. As an interactive command in the command interpreter you could use dir %userprofile%\desktop, and that also works via the Windows Run-dialog. Depending on the command interpreter's behavior for command line arguments it may work directly via CreateProcess, or not.
Generally, when using Windows API level functions it's preferable to use the wchar_t-based text based functions, i.e. define UNICODE before including <windows.h> (or use the ...W functions explicitly).
If you call CreateProcess() with the first parameter set to NULL, then you have to make sure that l1 starts with the module name to call.
As dir is an internal command of the command processor and not an executable, you have to use cmd as module name and give the rest of the parameter as cmd expects them.
So try the following:
string f = "cmd /c=dir desktop";

Make c++ program to pass input output to windows command prommpt interactively

I want to make a simple program that starts a cmd.exe parallely and takes input from the user as a command, which is then passed to the cmd.exe, after execution my program should take the output from cmd.exe and display it to the user. Basically an interface to a command prompt.
I don't want to use methods like system() as they start a new instance of cmd every time and I can't run commands like cd.
I tried it with the following code with which I am able to spawn a cmd and show initial line (copyright....), but passing commands simply returns the same line again.
#include <iostream>
#include <windows.h>
#include <process.h>
using namespace std;
DWORD WINAPI exec(LPVOID inputP){
char* input=(char*) inputP;
HANDLE stdinRd, stdinWr, stdoutRd, stdoutWr;
SECURITY_ATTRIBUTES sa = {sizeof(SECURITY_ATTRIBUTES), NULL, true};
STARTUPINFO si;
PROCESS_INFORMATION pi;
DWORD stuff;
char buff[1000];
//Create the main transfer pipe
if(!CreatePipe(&stdinRd, &stdinWr, &sa, 0) || !CreatePipe(&stdoutRd,&stdoutWr, &sa, 0)) {
cout<<"Pipe creation failed"<<endl;
}
//Get Process Startup Info
GetStartupInfo(&si);
si.dwFlags = STARTF_USESTDHANDLES | STARTF_USESHOWWINDOW;
si.wShowWindow = SW_SHOW;
si.hStdOutput = stdoutWr;
si.hStdError = stdoutWr;
si.hStdInput = stdinRd;
//Create the CMD Shell using the process startup info above
if(!CreateProcess("C:\\Windows\\System32\\cmd.exe", NULL, NULL, NULL, TRUE, 0, NULL, NULL, &si, &pi)) {
cout<<"Error Spawning Command Prompt."<<endl;
}
//Main while(1) Loop
while(1)
{
Sleep(100);
//Check if cmd.exe has not stoped
GetExitCodeProcess(pi.hProcess, &stuff);
//Stop the while loop if not active
if(stuff != STILL_ACTIVE) break;
//Copy Data from buffer to pipe and vise versa
PeekNamedPipe(stdoutRd, NULL, 0, NULL, &stuff, NULL);
ZeroMemory(buff, sizeof(buff));
//Read Console Output
ReadFile(stdoutRd, buff, 1000, &stuff, NULL);
//output
cout<<buff<<endl;
//Read data from stream and pipe it to cmd.exe
WriteFile(stdinWr, input, strlen(input), &stuff, NULL);
}
return 0;
}
int main() {
while(1){
char a[100];
cin>>a;
CreateThread(NULL, 0, (LPTHREAD_START_ROUTINE)exec, (LPVOID)a, 0, NULL);
}
}
Found my problem, was quite silly. Just need to pass a new line character so that cmd interprets the data as a command, i.e.,
cin>>a;
strcat(a,"\n");
and obviously make a single instance of cmd by calling the thread only once and passing parameters through global variables.

C++ CreateProcess - System Error #2 can't find file - what is wrong with my file path?

I am trying to open a PDF via Firefox with CreateProcess(), I am a beginner and know nothing about using CreateProcess, but in my last question someone pointed out the MSDN on it... it shows that:
To run a batch file, you must start the command interpreter;
set lpApplicationName to cmd.exe and set lpCommandLine to the
following arguments: /c plus the name of the batch file.
Therefore I created a batch file that runs perfectly fine with the system() command, there are no problems with the batch file.
I can't figure out why the system can't find the file and I don't know if its the batch file, the exe in the batch file, the PDF doc in the batch file or the location of cmd.exe... Any help is greatly appreciated...
void openPDF(char scansQueue[][MAX_NAME], int index)
{
// build batch file
char openPath[300];
char procCommand[MAX_NAME]="C:\\firefox";
char cmdEXE[MAX_NAME]="C:\\Windows\\System32\\cmd.exe";
fstream outfile;
outfile.open("C:\\firefox.bat");
copyCString(openPath,"\"C:\\Program Files (x86)\\Mozilla Firefox\\firefox.exe\"");
outfile << openPath;
outfile << ' ';
copyCString(openPath,"\"C:\\Scans\\");
catArray(openPath,scansQueue[index]);
catArray(openPath,"\"");
STARTUPINFOW si;
PROCESS_INFORMATION pi;
ZeroMemory( &si, sizeof(si) );
si.cb = sizeof(si);
ZeroMemory( &pi, sizeof(pi) );
cout<<"PROCESS ATTEMPT"<<endl;
if(!CreateProcess((LPCTSTR)cmdEXE ,(LPWSTR)procCommand, NULL, NULL, false, 0, NULL, NULL, &si, &pi))cout << GetLastError();cout<<"PROCESS FAILED TO EXECUTE!!!";
}
This assumes the whole batch file thing is part of an XY problem, in that you don't really need to make a batch file, you really just want to launch Firefox with a command line parameter.
I also assume you don't really need to pass the whole array of filenames with an index for which to use, instead you should just pass the filename by itself as I did where I called the function.
#include <Windows.h>
#include <stdio.h>
void MsgBoxLastError()
{
LPWSTR lpMsgBuf = NULL;
if(FormatMessage(
FORMAT_MESSAGE_ALLOCATE_BUFFER |
FORMAT_MESSAGE_FROM_SYSTEM |
FORMAT_MESSAGE_IGNORE_INSERTS,
NULL,
GetLastError(),
MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
(LPWSTR)&lpMsgBuf,
0, NULL ) != 0)
{
MessageBox(NULL, lpMsgBuf, L"Error", MB_OK);
}
LocalFree(lpMsgBuf);
}
void OpenWithFirefox(const char* Filename)
{
const WCHAR pathToFirefox[] = L"C:/Program Files (x86)/Mozilla Firefox/firefox.exe";
const WCHAR scanPrefix[] = L"file://C:/Scans/";
WCHAR fullCommandLine[MAX_PATH] = {0};
//Build full command line
swprintf_s(fullCommandLine, L"\"%s\" \"%s%S\"", pathToFirefox, scanPrefix, Filename);
STARTUPINFOW si;
PROCESS_INFORMATION pi;
ZeroMemory( &si, sizeof(si) );
si.cb = sizeof(si);
ZeroMemory( &pi, sizeof(pi) );
BOOL success = CreateProcess(NULL, fullCommandLine, NULL, NULL, false, 0, NULL, NULL, &si, &pi);
if(success)
{
CloseHandle(pi.hProcess);
CloseHandle(pi.hThread);
}
else
{
MsgBoxLastError();
}
}
int main()
{
const int MAX_NAME = 13;
char scansQueue[][MAX_NAME] =
{
"file1.pdf",
"file2.pdf"
};
for(int i = 0; i < 2; ++i)
{
OpenWithFirefox(scansQueue[i]);
}
return 0;
}

How to redirect in, out and err streams from process created with CreateProcess function? [duplicate]

I tried using CreateProcess to run a simple command like hg > test.txt. I tried running the string as a whole (as opposed to separating it into an application name and its parameters). Why does CreateProcess(0, "notepad.exe test.txt", ...) work but CreateProcess(0, "hg > test.txt", ...) does not?
The code below creates a console-less process with stdout and stderr redirected to the specified file.
#include <windows.h>
int _tmain(int argc, _TCHAR* argv[])
{
SECURITY_ATTRIBUTES sa;
sa.nLength = sizeof(sa);
sa.lpSecurityDescriptor = NULL;
sa.bInheritHandle = TRUE;
HANDLE h = CreateFile(_T("out.log"),
FILE_APPEND_DATA,
FILE_SHARE_WRITE | FILE_SHARE_READ,
&sa,
OPEN_ALWAYS,
FILE_ATTRIBUTE_NORMAL,
NULL );
PROCESS_INFORMATION pi;
STARTUPINFO si;
BOOL ret = FALSE;
DWORD flags = CREATE_NO_WINDOW;
ZeroMemory( &pi, sizeof(PROCESS_INFORMATION) );
ZeroMemory( &si, sizeof(STARTUPINFO) );
si.cb = sizeof(STARTUPINFO);
si.dwFlags |= STARTF_USESTDHANDLES;
si.hStdInput = NULL;
si.hStdError = h;
si.hStdOutput = h;
TCHAR cmd[]= TEXT("Test.exe 30");
ret = CreateProcess(NULL, cmd, NULL, NULL, TRUE, flags, NULL, NULL, &si, &pi);
if ( ret )
{
CloseHandle(pi.hProcess);
CloseHandle(pi.hThread);
return 0;
}
return -1;
}
You can't use stdout redirection in the command line passed to CreateProcess. To redirect stdout you need to specify a file handle for the output in the STARTUPINFO structure.
You are also making another, more subtle, mistake. The second parameter, lpCommandLine must point to writeable memory because CreateProcess overwrites the buffer. If you happen to be using the ANSI version of the function then you will get away with this, but not for the Unicode version.
The Unicode version of this function, CreateProcessW, can modify the contents of this string. Therefore, this parameter cannot be a pointer to read-only memory (such as a const variable or a literal string). If this parameter is a constant string, the function may cause an access violation.
Microsoft has an example how to redirect the standard output:
http://msdn.microsoft.com/en-us/library/ms682499(VS.85).aspx.
CreateProcess() launches processes, it is not a command line itnerpreter. It doesn't know what ">" is and won't do the stream redirection for you. You need to open the file test.txt yourself and pass the handle to it to CreateProcess inside the STARTUPINFO structure:
CreateProcess
STARTUPINFO
you should run process cmd.exe with params "/c command line".
This will redirect the output to a file or to organize a pipeline through CreateProcess.