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17 Writing Extensions for gawk

It is possible to add new functions written in C or C++ to gawk using dynamically loaded libraries. This facility is available on systems that support the C dlopen() and dlsym() functions. This chapter describes how to create extensions using code written in C or C++.

If you don’t know anything about C programming, you can safely skip this chapter, although you may wish to review the documentation on the extensions that come with gawk (see The Sample Extensions in the gawk Distribution), and the information on the gawkextlib project (see The gawkextlib Project). The sample extensions are automatically built and installed when gawk is.

NOTE: When --sandbox is specified, extensions are disabled (see Command-Line Options).

• Introduction
• Extension Licensing
• How It Works at a High Level
• API Description
• How gawk Finds Extensions
• Example: Some File Functions
• The Sample Extensions in the gawk Distribution
• The gawkextlib Project
• Summary
• Exercises