Hands-On System Programming with Linux

Refactoring glibc APIs from foo to foo_r

Of course, today, with MT applications being the de facto reality, what do we do? The glibc maintainers understand these issues, and have used precisely the refactoring techniques – passing additional parameters to avoid the usage of global and/or static variables (like we did previous with our ch16/mt_iobuf_rfct.c code), including using parameters as return values—to refactor standard glibc functions to become thread-safe. The glibc naming convention is if the older function is named foo, the refactored, usually reentrant- and thread-safe, version is named foo_r.

To help lend clarity to this discussion, let's take an example of a glibc API that has both the older foo and the newer foo_r functionality. ...