5.22 GH: A Portable C to Scheme Interface

This chapter shows how to use the GH interface to call Guile from your application's C code, and to add new Scheme level procedures to Guile whose behaviour is specified by application specific code written in C.

Note, however, that the GH interface is now deprecated, and developers are encouraged to switch to using the scm interface instead. Therefore, for each GH feature, this chapter also documents how to achieve the same result using the scm interface.

• GH deprecation: Why the GH interface is now deprecated.
• Transitioning away from GH
• GH preliminaries
• Data types and constants defined by GH
• Starting and controlling the interpreter
• Error messages
• Executing Scheme code
• Defining new Scheme procedures in C
• Converting data between C and Scheme
• Type predicates
• Equality predicates
• Memory allocation and garbage collection
• Calling Scheme procedures from C