CDECL(1) UNIX System V CDECL(1)
NAME
cdecl - Compose C declarations
SYNOPSIS
cdecl
DESCRIPTION
Cdecl is a program for encoding and decoding C type-
declarations. It reads standard input for statements in the
language described below. The results are written on
standard output.
Cdecl's scope is intentionally small. It doesn't help you
figure out storage classes or initializations.
COMMAND LANGUAGE
There are four statements in the language. The "declare"
statement composes a C type-declaration from a verbose
description. The "cast" statement composes a C type-cast as
might appear in an expression. The "explain" statement
decodes a C type-declaration, producing a verbose
description. The "help" statement describes the others.
The following grammar describes the language. In the
grammar, words in "<>" are non-terminals, bare lower-case
words are terminals that stand for themselves. Bare upper-
case words are other lexical tokens: NOTHING means the
empty string; NAME means a C identifier; NUMBER means a
string of decimal digits; and NL means the new-line
character.
<program> ::= NOTHING
| <program> <stat> NL
<stat> ::= NOTHING
| declare NAME as <decl>
| cast NAME into <decl>
| explain <cdecl>
| help
<decl> ::= array of <decl>
| array NUMBER of <decl>
| function returning <decl>
| function ( NAME ) returning <decl>
| pointer to <decl>
| <type>
<cdecl> ::= <cdecl1>
| * <cdecl>
<cdecl1> ::= <cdecl1> ( )
| <cdecl1> [ ]
| <cdecl1> [ NUMBER ]
| ( <cdecl> )
| NAME
<type> ::= <typename> | <modlist>
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CDECL(1) UNIX System V CDECL(1)
| <modlist> <typename>
| struct NAME | union NAME | enum NAME
<typename> ::= int | char | double | float
<modlist> ::= <modifier> | <modlist> <modifier>
<modifier> ::= short | long | unsigned
EXAMPLES
To declare an array of pointers to functions like malloc(3),
do declare fptab as array of pointer to function returning
pointer to char The result of this command is char
*(*fptab[])() When you see this declaration in someone
else's code, you can make sense out of it by doing explain
char *(*fptab[])() The proper declaration for signal(2)
cannot be described in cdecl's language (it can't be
described in C either). An adequate declaration for most
purposes is given by declare signal as function returning
pointer to function returning int The function declaration
that results has two sets of empty parentheses. The author
of such a function might wonder where the parameters go.
declare signal as function (args) returning pointer to
function returning int provides the solution: int
(*signal(args))()
DIAGNOSTICS
The declare statement tries to point out constructions that
are not supported in C. Also, certain non-portable
constructs are flagged.
Syntax errors cause the parser to play dead until a newline
is read.
SEE ALSO
Section 8.4 of the C Reference Manual.
BUGS
The pseudo-English syntax is excessively verbose.
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