This describes the embedded SQL package for PostgreSQL. It works with C and C++. It was written by Linus Tolke (<linus@epact.se>) and Michael Meskes (<meskes@debian.org>). The package is installed with the PostgreSQL distribution, and carries a similar license.
Embedded SQL has advantages over other methods for handling SQL queries. It takes care of the tedious passing of information to and from variables in your C or C++ program. Many RDBMS packages support this embedded language.
There is an ANSI standard describing how the embedded language should work. ecpg was designed to match this standard as much as possible. It is possible to port embedded SQL programs written for other RDBMS to PostgreSQL.
Read the upstream documentation. For corrections, first check the current version.