_spawnvpe, _wspawnvpe

Create and execute a new process.

int _spawnvpe( int mode, const char *cmdname, const char *const *argv, const char *const *envp );

int _wspawnvpe( int mode, const wchar_t *cmdname, const wchar_t *const *argv, const wchar_t *const *envp );

For additional compatibility information, see Compatibility in the Introduction.

Libraries

Return Value

The return value from a synchronous _spawnvpe or _wspawnvpe (_P_WAIT specified for mode) is the exit status of the new process. The return value from an asynchronous _spawnvpe or _wspawnvpe (_P_NOWAIT or _P_NOWAITO specified for mode) is the process handle. The exit status is 0 if the process terminated normally. You can set the exit status to a nonzero value if the spawned process specifically calls the exit routine with a nonzero argument. If the new process did not explicitly set a positive exit status, a positive exit status indicates an abnormal exit with an abort or an interrupt. A return value of –1 indicates an error (the new process is not started). In this case, errno is set to one of the following values:

E2BIG

Argument list exceeds 1024 bytes

EINVAL

mode argument is invalid

ENOENT

File or path is not found

ENOEXEC

Specified file is not executable or has invalid executable-file format

ENOMEM

Not enough memory is available to execute new process

Parameters

mode

Execution mode for calling process

cmdname

Path of file to be executed

argv

Array of pointers to arguments

envp

Array of pointers to environment settings

Remarks

Each of these functions creates and executes a new process, passing an array of pointers to command-line arguments and an array of pointers to environment settings. These functions use the PATH environment variable to find the file to execute.

See Also   abort, atexit, _exec Functions, exit, _flushall, _getmbcp, _onexit, _setmbcp, system

Example

/* SPAWN.C: This program accepts a number in the range
 * 1-8 from the command line. Based on the number it receives,
 * it executes one of the eight different procedures that
 * spawn the process named child. For some of these procedures,
 * the CHILD.EXE file must be in the same directory; for
 * others, it only has to be in the same path.
 */

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

char *my_env[] =
{
   "THIS=environment will be",
   "PASSED=to child.exe by the",
   "_SPAWNLE=and",
   "_SPAWNLPE=and",
   "_SPAWNVE=and",
   "_SPAWNVPE=functions",
   NULL
};

void main( int argc, char *argv[] )
{
   char *args[4];

   /* Set up parameters to be sent: */
   args[0] = "child";
   args[1] = "spawn??";
   args[2] = "two";
   args[3] = NULL;

   if (argc <= 2)
   {
      printf( "SYNTAX: SPAWN <1-8> <childprogram>\n" );
      exit( 1 );
   }

   switch (argv[1][0])   /* Based on first letter of argument */
   {
   case '1':
      _spawnl( _P_WAIT, argv[2], argv[2], "_spawnl", "two", NULL );
      break;
   case '2':
      _spawnle( _P_WAIT, argv[2], argv[2], "_spawnle", "two", 
               NULL, my_env );
      break;
   case '3':
      _spawnlp( _P_WAIT, argv[2], argv[2], "_spawnlp", "two", NULL );
      break;
   case '4':
      _spawnlpe( _P_WAIT, argv[2], argv[2], "_spawnlpe", "two", 
                NULL, my_env );
      break;
   case '5':
      _spawnv( _P_OVERLAY, argv[2], args );
      break;
   case '6':
      _spawnve( _P_OVERLAY, argv[2], args, my_env );
      break;
   case '7':
      _spawnvp( _P_OVERLAY, argv[2], args );
      break;
   case '8':
      _spawnvpe( _P_OVERLAY, argv[2], args, my_env );
      break;
   default:
      printf( "SYNTAX: SPAWN <1-8> <childprogram>\n" );
      exit( 1 );
   }
   printf( "from SPAWN!\n" );
}

Output

SYNTAX: SPAWN <1-8> <childprogram>