Add note about old-style function declarations to the manual.

[cdecl99.git] / doc / man / libcdecl.3

diff --git a/doc/man/libcdecl.3 b/doc/man/libcdecl.3
index 489d7a9ef7eb8fce9a409c70d1aab18735e2efdd..a4dc5f45581fe9b85b7226411c5e9240dfd0f1a4 100644 (file)
--- a/doc/man/libcdecl.3
+++ b/doc/man/libcdecl.3
@@ -17,6 +17,7 @@
 .Fd const struct cdecl_error *cdecl_get_error(void);
 .Pp
 .Fd int cdecl_spec_kind(struct cdecl_declspec *spec);
+.Fd bool cdecl_is_abstract(struct cdecl_declarator *declarator);
 .Sh DESCRIPTION
 .Nm
 provides support for parsing C declarations and translating them to something
@@ -193,11 +194,21 @@ member is interpreted as "function returning child".
 .El
 .Ss Terminal Declarators
 Null and identifier declarators have no children and are thus leaf nodes.  A
-null declarator indicates an abstract declarator; that is, one which does not
-declare any identifier.  Such declarators appear in type names and possibly
-function parameters.  An identifier declarator has the obvious meaning; the
+null declarator is not strictly a C language construct, but is used by
+.Nm
+to indicate an abstract declarator; that is, one which does not declare any
+identifier.  Such declarators appear in type names and possibly function
+parameters.  An identifier declarator has the obvious meaning; the
 .Va ident
 union member points to the C string containing the identifier.
+.Pp
+Since a null declarator may be deeply nested in the declarator chain, the
+function
+.Pp
+.Fd bool cdecl_is_abstract(struct cdecl_declarator *declarator);
+.Pp
+can be used to determine whether or not a given declarator declares an
+identifier.  The result is true if and only if the declarator is abstract.
 .Ss Pointer Declarators
 .Bd -literal -offset indent
 struct cdecl_pointer {
@@ -246,6 +257,13 @@ each function parameter has exactly one full declarator (abstract or
 otherwise).   If
 .Va variadic
 is true, then the function is variadic.
+.Pp
+Note that old-style function declarations with non-empty identifier lists are
+not directly represented here: this is because they are syntactically identical
+to a prototype where every parameter is a typedef name.  Since
+.Nm
+isn't a C compiler, there is no way for the parser to tell these two kinds of
+declarations apart.
 .Sh ERROR HANDLING
 Some functions in
 .Nm