如何让Google Test检测Linux上的线程数？

Question

When running the death tests written using Google Test framework the following warning is produced for each of the tests:

[WARNING] .../gtest-death-test.cc:789:: Death tests use fork(), which is unsafe
particularly in a threaded context. For this test, Google Test couldn't detect
the number of threads.

Is there a way to make Google Test detect the number of threads on Linux?

Answer 1

I've looked at the source code and it turned out that detection of the number of threads is implemented only for MacOS X and QNX, but not on Linux or other platforms. So I implemented missing functionality myself by counting the number of entries in /proc/self/task . Since it might be useful for others I'm posting it here (I've also sent it to the Google Test group ):

size_t GetThreadCount() {
  size_t thread_count = 0;
  if (DIR *dir = opendir("/proc/self/task")) {
    while (dirent *entry = readdir(dir)) {
      if (strcmp(entry->d_name, ".") != 0 && strcmp(entry->d_name, "..") != 0)
        ++thread_count;
    }
    closedir(dir);
  }
  return thread_count;
}

As of 25 August 2015, Google Test implements GetThreadCount on Linux :

size_t GetThreadCount() {
  const string filename =
      (Message() << "/proc/" << getpid() << "/stat").GetString();
  return ReadProcFileField<int>(filename, 19);
}

Answer 2

If you don't care much about the test execution time, a convenient alternative is to use:

::testing::FLAGS_gtest_death_test_style = "threadsafe";

More details here .