PRODUCT  :  Borland C++                            NUMBER  :  727
  VERSION  :  2.0
       OS  :  DOS
     DATE  :  September 18, 1991                       PAGE  :  1/1

    TITLE  :  Redirecting Output Before Spawn









  /************************************************************
   How to redirect output before spawning a child process.
   ************************************************************/

  FILE *fp;
  int handle;

  fp=fopen( <parms. to open file where to redirect stdout> );
  /* in this case, use "NUL" as the file, this is DOS's NULL device
  */

  handle=dup(fileno(stdout));
  dup2(fileno(fp),fileno(stdout));
  execlp ( <whatever parameters you need> );
  dup2(handle,fileno(stdout));

  /*This will duplicate the file handle stdout to the FILE pointer
  fp. Then dup2 is used to replace stdout with the new file opened
  with fopen. Next, make your call to spawn. Finally, use dup2 with
  the saved handle variable to restore stdout. */