Question

So, I have a tiny fragment of C code running on a windows box, that reads:

/* invoke command */
impl->procHandle = _spawnve(_P_NOWAIT, command, vargs, env);
if (impl->procHandle == -1) {
  printf("Failed to invoke command: %s\n", strerror(errno));
  impl->busy = false;
}
printf("VICTORY\n");

I wrote some unit tests around this where my “command” was C:\windows\system32\ipconfig.exe and it works, no problem.

Tried to use it for an application launcher… doo doo. Failed with the helpful error:

The application failed to initialize properly (0xc0150004). 
Click on OK to terminate the application.

Ok… searching around I discovered that the error code is STATUS_SXS_ASSEMBLY_NOT_FOUND, and it happens when I try to launch notepad.exe as well. Missing assemblies?

Why is this happening?

How can I work around it?

I’m just guessing here, but I suspect it has something to do with needing the PATH variable to be set in the _spawnve(), but I dont know what it should be. I tried passing in the path, but that doesn’t seem to help. Running this code:

int offset = 0;
while (vargs[offset] != NULL) {
  printf("vargs %d: %s\n", offset, vargs[offset]);
  ++offset;
}
offset = 0;
while (env[offset] != NULL) {
  printf("env %d: %s\n", offset, env[offset]);
  ++offset;
}

Yeilds:

vargs 0: C:\windows\system32\notepad.exe
env 0: PATH=c:\WINDOWS\system32

ie. I am passing in argv[0], and a path value; not other env variables or arguments.

Any ideas?

—

Edit:

So, it seems this error is occurring because the PATH is not correctly set when I invoke the command using _spawnve().

This is made obvious by invoking either _spawnv() or _spawnvpe(), both of which seem to work correctly.

However, that doesn’t really help me, because I need to specify an additional PATH component for the application when it runs. Passing PATH=… into _spawnvpe() causes the same error, and obviously _spawnv is no used because it doesn’t allow you to specify the PATH.

So really, the answer to this question is: Because the PATH variable is wrong.

…but I still have no idea what it should be. There seem to be no working examples of this that I can find anywhere. I’ll accept any answer that links to an example of coding using _spawnve() or _spawnvpe() and passing the PATH variable into it (and working).

Edit #2:

Really. No, actually, this doesn’t work. Here’s an example of it not working. Forget linking to an example that works; just modify my example and post a diff that 1) passes in PATH and 2) runs without an error.

Nb. Want to see it work? change to _spawnv() or make the env value NULL and it runs just fine.

#include <stdio.h>
#include <windows.h>
#include <process.h>
#include <errno.h>

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

  char *path_value;
  char buffer[4000];
  const char *env[2];
  const char *args[1];
  char *command;
  int result;
  intptr_t procHandle;

  path_value = getenv("PATH");
  sprintf(buffer, "PATH=%s", path_value);
  env[0] = buffer;
  env[1] = NULL;

  args[0] = NULL;

  int offset = 0;
  while (env[offset] != NULL) {
    printf("env %d: %s\n", offset, env[offset]);
    ++offset;
  }

  offset = 0;
  while (args[offset] != NULL) {
    printf("arg %d: %s\n", offset, args[offset]);
    ++offset;
  }

  command = "C:\\windows\\system32\\notepad.exe";

  procHandle = _spawnvpe(_P_NOWAIT, command, args, NULL);
  if (procHandle == -1) {
    printf("Failed to invoke command: %s\n", strerror(errno));
    exit(1);
  }

  _cwait(&result, procHandle, 0);
  if (result != 0)
    printf("Command exited with error code %d\n", result);
}

Output:

env 0: PATH=.;c:\Program Files\Common Files\Microsoft Shared\Windows Live;c:\WINDOWS\system32;c:\WINDOWS;c:\WINDOWS\System32\Wbem;c:\Program Files\Microsoft SQL Server\100\Tools\Binn\;c:\Program Files\Microsoft SQL Server\100\DTS\Binn\;c:\Program Files\CMake 2.8\bin;c:\Program Files\Microsoft ASP.NET\ASP.NET Web Pages\v1.0\;c:\Program Files\Common Files\Microsoft Shared\Windows Live
Command exited with error code -1072365564

Answer 1

This is wrong:

const char *args[1];
args[0] = NULL;

you need

const char *args[2];
args[0] = "notepad";
args[1] = NULL;

Other than that, your example code works, at least when compiled with Visual Studio 2010. I’ve tested it on both Windows 7 and Windows XP, and it works. Notepad runs.

What compiler are you using?