SWPRUNCMD / SWPRUNCMDBAS
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  Function : Execute a child process.

  Syntax   : lValue = SWPRUNCMD(cCommand, nuMem, cRunPath, cTempPath)

  Return   : TRUE if the command interpreter was executed

  This function executes a child process of the current program, freeing
  memory occupied by the parent program.

  The parameters to SWPRUNCMD() are as follows:

  cCommand:  The name of the program, batch file or DOS internal command
  to be executed, followed by any required parameters. An empty string
  will cause the command interpreter to be loaded, giving a DOS prompt.

  nuMem:  The amount of memory in kilobytes (kb) to be freed prior to
  executing the child process.  If this parameter is passed as zero, as
  much memory as possible will be freed.

  cRunPath:  The drive and directory to make current prior to executing
  the child process.

  cTempPath:  The drive and directory where the swap function should
  create a disk swap file containing the image (or partial image) of the
  parent program.  Note that XMS and EMS memory will be used in preference
  to a disk swap file if available provided their use has not been
  prohibited through the use of SWPUSEEMS() and SWPUSEXMS().

  Note that this parameter may be overridden at runtime through the use of
  the SWAP environment variable. For example :

  SET SWAP=E:\TEMP;

  will cause the temporary diskfile to be created in F:\TEMP, regardless
  of the value passed as a parameter to the SWPRUNCMD().

  The swap function will always invoke the current command interpreter as
  specified in the COMSPEC environment variable, which in turn will
  execute cCommand.  This allows the parent program to execute any
  internal or external DOS command, a batch file or any program which can
  be executed from the DOS prompt.  The return code of the child process
  can be retrieved using the function SWPERRLEV().

  The return value is a logical (boolean) value indicating the success of
  the SWPRUNCMD() call. Following an unsuccessful call to SWPRUNCMD(), the
  program can use SWPERRMAJ() and SWPERRMIN() to determine the nature of
  the error.

  Example  :
  success = SWPRUNCMD("",0,"","")

  Shell to DOS, freeing as much memory as possible, save swap file to
  current directory if required.

  success = SWPRUNCMD("WIN",0,"C:\WINDOWS","F:\")

  This command will execute Microsoft Windows, freeing as much memory as
  possible. The swap function will change drive and directory to
  C:\WINDOWS prior to executing the WIN command. If a temporary disk swap
  file is required, it will be created on F:\

  success = SWPRUNCMD("DIR /W",100,"","")

  Execute the DOS DIR command, first freeing 100KB,  save swap disk file
  to the current directory if required .