Function kwsysProcess_WaitForData

Source/kwsys/ProcessUNIX.c:1075–1134

                                   kwsysProcessWaitData* wd);

int kwsysProcess_WaitForData(kwsysProcess* cp, char** data, int* length,
                             double* userTimeout)
{
  kwsysProcessTime userStartTime = { 0, 0 };
  kwsysProcessWaitData wd = { 0, kwsysProcess_Pipe_None, 0, 0, { 0, 0 } };
  wd.UserTimeout = userTimeout;
  /* Make sure we are executing a process.  */
  if (!cp || cp->State != kwsysProcess_State_Executing || cp->Killed ||
      cp->TimeoutExpired) {
    return kwsysProcess_Pipe_None;
  }

  /* Record the time at which user timeout period starts.  */
  if (userTimeout) {
    userStartTime = kwsysProcessTimeGetCurrent();
  }

  /* Calculate the time at which a timeout will expire, and whether it
     is the user or process timeout.  */
  wd.User = kwsysProcessGetTimeoutTime(cp, userTimeout, &wd.TimeoutTime);

  /* Data can only be available when pipes are open.  If the process
     is not running, cp->PipesLeft will be 0.  */
  while (cp->PipesLeft > 0 &&
         !kwsysProcessWaitForPipe(cp, data, length, &wd)) {
  }

  /* Update the user timeout.  */
  if (userTimeout) {
    kwsysProcessTime userEndTime = kwsysProcessTimeGetCurrent();
    kwsysProcessTime difference =
      kwsysProcessTimeSubtract(userEndTime, userStartTime);
    double d = kwsysProcessTimeToDouble(difference);
    *userTimeout -= d;
    if (*userTimeout < 0) {
      *userTimeout = 0;
    }
  }

  /* Check what happened.  */
  if (wd.PipeId) {
    /* Data are ready on a pipe.  */
    return wd.PipeId;
  }
  if (wd.Expired) {
    /* A timeout has expired.  */
    if (wd.User) {
      /* The user timeout has expired.  It has no time left.  */
      return kwsysProcess_Pipe_Timeout;
    }

    /* The process timeout has expired.  Kill the children now.  */
    kwsysProcess_Kill(cp);
    cp->Killed = 0;
    cp->TimeoutExpired = 1;
    return kwsysProcess_Pipe_None;
  }
  /* No pipes are left open.  */