Problems with spawnl()

[Mr.Modem]

I'm writing an app that needs to be able to run other applications. I chose the spawnl function in process.h for the purpose. Here's a little test program I wrote:

#include <stdio.h>
#include <stdlib.h>
#include <process.h>

///////////////////////////////////////////////////////////////////////
//////Small app that launches itself using the spanwl function/////////
///////////////////////////////////////////////////////////////////////

int main(int argc, char *argv[])
{
int error;
if(argc == 1){
        error = spawnl(P_WAIT,"D:\\Dev\\Projects\\Tests\\Spawn\\spawn.exe",
        "D:\\Dev\\Projects\\Tests\\Spawn\\spawn.exe","\"This is the first argument passed by spawn.exe!\"",NULL );
        if(error == 0)printf("Program lauched successfully!\n");
        else {
             printf("%d\n",error);
             system("PAUSE");
        }
}
else {
     printf("%s\n\n",argv[1]);
     system("PAUSE");
}	
 return 0;
}

This program works fine. It launches the app succsessfully. But when I try to launch an app that have a space in the file path (for example: D:\Dev\Projects\Tests\Spawn 1\spawn.exe) it doesn't work. Is there a solution to this problem?

[ZuK]

You could try to quote the path
e.g.

error = spawnl(P_WAIT,"\"D:\\Dev\\Projects\\Tests\\Spawn 1\\spawn.exe\"",
        "\"D:\\Dev\\Projects\\Tests\\Spawn 1\\spawn.exe\"","\"This is the first argument passed by spawn.exe!\"",NULL );
        if(error == 0)printf("Program lauched successfully!\n");

using forward slashes would make it easier to read.

error = spawnl(P_WAIT,"\"D:/Dev/Projects/Tests/Spawn 1/spawn.exe\"",
        "\"D:/Dev/Projects/Tests/Spawn 1/spawn.exe\"","\"This is the first argument passed by spawn.exe!\"",NULL );
        if(error == 0)printf("Program lauched successfully!\n");

Kurt

[Mr.Modem]

I've already tried that but it doesn't work. Spawnl returns -1.

[Salem]

Which OS/Compiler are you using?

[ZuK]

I've already tried that but it doesn't work. Spawnl returns -1.

I know windows doesn't support filenames containing spaces very well.
One way could be to find out that funny 8.3-style path and use that.
Kurt

[Mr.Modem]

Which OS/Compiler are you using?

I use DevCpp.

I know windows doesn't support filenames containing spaces very well.
One way could be to find out that funny 8.3-style path and use that.
Kurt

That wouldn't be a good solution. The program I'm planning to make will read the program path from an ini file and launch it. Then I would need a function to convert the path to the 8.3 format. There must be an easier solution.

EDIT: After I looked in your FAQ I found a solution to the problem. It isn't exactly what I want but it works:

#include <windows.h>

int main(void)
{
  char szPath[] = "C:\\Program\\Windows Media Player\\wmplayer.exe";
  PROCESS_INFORMATION pif;  //Gives info on the thread and..
                           //..process for the new process
  STARTUPINFO si;          //Defines how to start the program

  ZeroMemory(&si,sizeof(si)); //Zero the STARTUPINFO struct
  si.cb = sizeof(si);         //Must set size of structure

  BOOL bRet = CreateProcess(
        szPath, //Path to executable file
        NULL,   //Command string - not needed here
        NULL,   //Process handle not inherited
        NULL,   //Thread handle not inherited
        FALSE,  //No inheritance of handles
        0,      //No special flags
        NULL,   //Same environment block as this prog
        NULL,   //Current directory - no separate path
        &si,    //Pointer to STARTUPINFO
        &pif);   //Pointer to PROCESS_INFORMATION

  if(bRet == FALSE)
  {
    MessageBox(HWND_DESKTOP,"Unable to start program","",MB_OK);
    return 1;
  }

  CloseHandle(pif.hProcess);   //Close handle to process
  CloseHandle(pif.hThread);    //Close handle to thread

  return 0;
}

The only problem is that it's limited to windows. Are there any other, more portable functions that does the same thing?

[ZuK]

That wouldn't be a good solution. The program I'm planning to make will read the program path from an ini file and launch it. Then I would need a function to convert the path to the 8.3 format.

you could use GetShortPathName() to convert the path.
Kurt

[Mr.Modem]

How does GetShortPathName() work? I've never done any windows programming before.

[Salem]

http://msdn.microsoft.com/library/de...rtpathname.asp
You give it a long path, and somewhere to put the short path.

[Mr.Modem]

I tried to use an 8.3 file path but it didn't work either. Damn windows!

#include <stdio.h>
#include <stdlib.h>
#include <process.h>

///////////////////////////////////////////////////////////////////////
//////Small app that launches itself using the spanwl function/////////
///////////////////////////////////////////////////////////////////////

int main(int argc, char *argv[])
{
int error;


if(argc == 1){
        error = spawnl(P_WAIT,"C:\\PROGRAM\\WINDOW~1\\WMPLAY~1.exe",
        "C:\\PROGRAM\\WINDOW~1\\WMPLAY~1.exe","\"This is the first argument passed by spawn.exe!\"",NULL );
        if(error == 0)printf("Program lauched successfully!\n");
        else {
             printf("%d\n",error);
             system("PAUSE");
        }
}
else {
     printf("%s\n\n",argv[1]);
     system("PAUSE");
}	
 return 0;
}

[Salem]

> "\"This is the first argument passed by spawn.exe!\""
Maybe it works all along, and it's just windows media player rejecting your attempt to post garbage strings to it.

[Mr.Modem]

Oops, I forgot to take away that argument. But it doesn't really matter. The program don't start anyway.