Method SpawnBuildDaemon

Source/cmInstrumentation.cxx:844–870

* Called by ctest --start-instrumentation. * * This creates a detached process which waits for the parent process (i.e., * the build system) to die before running the postBuild hook. In this way, the * postBuild hook triggers after every invocation of the build system, * regardless of whether the build passed or failed. */

 * regardless of whether the build passed or failed.
 */
int cmInstrumentation::SpawnBuildDaemon()
{
  // Do not inherit handles from the parent process, so that the daemon is
  // fully detached. This helps prevent deadlock between the two.
  uv_disable_stdio_inheritance();

  // preBuild Hook
  if (this->LockBuildDaemon()) {
    // Release lock before spawning the build daemon, to prevent blocking it.
    this->buildLock.Release();
    this->CollectTimingData(cmInstrumentationQuery::Hook::PreBuild);
  }

  // postBuild Hook
  auto ppid = uv_os_getppid();
  if (ppid) {
    std::vector<std::string> args;
    args.push_back(cmSystemTools::GetCTestCommand());
    args.push_back("--wait-and-collect-instrumentation");
    args.push_back(this->binaryDir);
    args.push_back(std::to_string(ppid));
    auto builder = cmUVProcessChainBuilder().SetDetached().AddCommand(args);
    auto chain = builder.Start();
    uv_run(&chain.GetLoop(), UV_RUN_DEFAULT);
  }
  return 0;
}

// Prevent multiple build daemons from running simultaneously
bool cmInstrumentation::LockBuildDaemon()