Ceph

David Zafman wrote:

We are using rand() throughout the code which man says isn't thread safe. We should determine if rand() with c++11 is thread safe or not. If it isn't use some other variant like rand_r(), boost? or c++11 features.

The rand() function is not thread-safe. rand() range is often significantly smaller than you want it to be. The C++ <random> library gives you much more powerful PRNGs.

Just to make sure the signal isn't lost in the noise, the facility in this PR is an interface to the C++11 standard random number facility that will be used to provide fixes for this bug report, once approved:
https://github.com/ceph/ceph/pull/15341