Rex Jaeschke
Computer Consultant
I am a consultant, author, and a leader and designer of seminars, specializing in the programming languages C, C++, C#, and Java™. I am also involved in a number of U.S. and international standards committees.


To see my personal blog (on which I post a 6-8-page essay each month) click here.


In 1989, my book Portability and the C Language was published. Starting in 2021, I spent a great deal of time and effort revising it to match that language’s evolution over the previous 32 years. Late in 2022, I donated the final result to Wikibooks (a sister site to Wikipedia) where it can be read and maintained by members of the public. Click here to see that revised book.

As part of my work for Facebook, I wrote the first formal specification for the PHP language. This spec is available to the public at I also wrote one for Hack, Facebook's strongly typed language that is built on PHP. That spec is available at