This chapter presents a summary of the Tcl C-language interface. Everything described here is defined in the header file tcl.h, part of the Tcl distribution. For clarity, ANSI C function prototypes are shown here, although the actual header file supports non-ANSI compilers.

To avoid name conflicts, all functions are prefixed with Tcl_ and constants are prefixed with TCL_.

See the full Tcl reference documentation for the most detailed and up-to-date information. C interfaces are typically found in Section 3 of the Tcl manpages.