13.1.2 Macros c2x recognizes

Here are the macros you can use in your source code from which c2x can construct initialization code:

     /* procedures */
     SCM_DEFINE (FNAME, PRIMNAME, REQ, OPT, VAR, ARGLIST, DOCSTRING)
     
     SCM_PROC (RANAME, STR, REQ, OPT, VAR, CFN)
     SCM_REGISTER_PROC (RANAME, STR, REQ, OPT, VAR, CFN)
     
     SCM_GPROC (RANAME, STR, REQ, OPT, VAR, CFN, GF)
     
     /* everything else */
     SCM_SYMBOL (c_name, scheme_name)
     SCM_GLOBAL_SYMBOL (c_name, scheme_name)
     
     SCM_KEYWORD (c_name, scheme_name)
     SCM_GLOBAL_KEYWORD (c_name, scheme_name)
     
     SCM_VCELL (c_name, scheme_name)
     SCM_GLOBAL_VCELL (c_name, scheme_name)
     
     SCM_VCELL_INIT (c_name, scheme_name, init_val)
     SCM_GLOBAL_VCELL_INIT (c_name, scheme_name, init_val)

REQ and OPT are numbers indicating required and optional argument counts, respectively; VAR is a number that, if non-zero, means the function will accept any remaining arguments as a list; DOCSTRING is a string (use \n\ at eol for multi-line); FNAME is a C-language identifier, CFN and GF and c_name likewise; PRIMNAME is a string denoting the name available to Scheme code, STR and scheme_name likewise; RANAME is the name of the static string (must match that declared by the associated definition of cpp macro FUNC_NAME); ARGLIST is an argument list (in parentheses); and lastly, init_val is a expression suitable for initializing a new variable.

For procedures, you can use SCM_DEFINE for most purposes. Use SCM_PROC along with SCM_REGISTER_PROC when you don't want to be bothered with docstrings. Use SCM_GPROC for generic functions (see GOOPS). All procedures are declared static with return type SCM.

For everything else, use the appropriate macro (SCM_SYMBOL for symbols, and so on). The "_GLOBAL_" variants omit static declaration.

All these macros should be used at top-level, outside function bodies. Also, it's a good idea to define FUNC_NAME immediately after using SCM_DEFINE (and similar), and then the function body, and then #undef FUNC_NAME.

See How c2x works, and also libguile source, for examples. See Subrs, for details on argument passing and how to write C functions.