Just a quick note about transference -- applying a concept from one field to another. I'm in the process of getting familiar with IPC::Run and in the process of writing a test script, I also built a C program that I could insert some sleeps into so as to try out the timer built into the module.

My original code was something like this:

#include <stdio.h>
#include <unistd.h>     /* For usleep */

/*  Fake version of bc to test timeouts  */

char *apszBanner[] = {
      "bc 0.6",
      "This is a fake version of bc.",
      "Don't trust any of the answers provided.",
      "Really, don't!",
      NULL
     };

int main ( int iArgC, char *apszArgV[] )
{
    char    *pszLine, szLine[80];

    int     i;

    /* sleep ( 5 ); */
    for ( i = 0; apszBanner[i]; i++ ) {

      puts ( apszBanner[i] );
    }
    sleep ( 5 );
    
    while ( pszLine = fgets ( szLine, sizeof(szLine), stdin ) ) {

      *(pszLine + strlen(pszLine) - 1) = '\0';
      printf ( "Got %s, the answer is 42.\n", pszLine );
    }
    return 0;   /*  Zero is success, right?  */
}
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To my consternation, the output didn't come out when I expected, but driving to chorus last night through horrendous traffic I was thinking about this and that, and on Yonge St, waiting for a light, I saw the light: I was suffering from buffering!

So, this morning, after dealing with the latest Production problem, I added fflush to my code:

#include <stdio.h>
#include <unistd.h>     /* For usleep */

/*  Fake version of bc to test timeouts  */

char *apszBanner[] = {
      "bc 0.6",
      "This is a fake version of bc.",
      "Don't trust any of the answers provided.",
      "Really, don't!",
      NULL
     };

int main ( int iArgC, char *apszArgV[] )
{
    char    *pszLine, szLine[80];

    int     i;

    /* sleep ( 5 ); */
    for ( i = 0; apszBanner[i]; i++ ) {

      puts ( apszBanner[i] );
    }
    fflush ( stdout );
    sleep ( 5 );
    
    while ( pszLine = fgets ( szLine, sizeof(szLine), stdin ) ) {

      *(pszLine + strlen(pszLine) - 1) = '\0';
      printf ( "Got %s, the answer is 42.\n", pszLine );
      fflush ( stdout );
    }
    return 0;   /*  Zero is success, right?  */
}
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And presto! Problem solved. Buffering and transference. So cool.