cproto - generate C function prototypes and convert function definitions
cproto [ option ... ] [ file ... ]
Cproto generates function prototypes for functions defined in the specified C source files
to the standard output. The function definitions may be in the old style or ANSI C style.
Optionally, cproto also outputs declarations for variables defined in the files. If no
file argument is given, cproto reads its input from the standard input.
By giving a command line option, cproto will also convert function definitions in the
specified files from the old style to the ANSI C style. The original source files along
with files specified by
directives appearing in the source code will be overwritten with the converted code. If
no file names are given on the command line, then the program reads the source code from
the standard input and outputs the converted source to the standard output.
If any comments appear in the parameter declarations for a function definition, such as in
main (argc, argv)
int argc; /* number of arguments */
char *argv; /* arguments */
then the converted function definition will have the form
int argc, /* number of arguments */
char *argv /* arguments */
Otherwise, the converted function definition will look like
main (int argc, char *argv)
Cproto can optionally convert function definitions from the ANSI style to the old style.
In this mode, the program also converts function declarators and prototypes that appear
outside function bodies. This is not a complete ANSI C to old C conversion. The program
does not change anything within function bodies.
Cproto can optionally generate source in lint-library format. This is useful in environ-
ments where the lint utility is used to supplement prototype checking of your program.
-e Output the keyword extern in front of every generated prototype or declaration that
has global scope.
-f n Set the style of generated function prototypes where n is a number from 0 to 3.
For example, consider the function definition
main (argc, argv)
If the value is 0, then no prototypes are generated. When set to 1, the output is:
int main(/*int argc, char *argv*/);
For a value of 2, the output has the form:
int main(int /*argc*/, char */*argv*/);
The default value is 3. It produces the full function prototype:
int main(int argc, char *argv);
-l Generate text for a lint-library (overrides the "-f" option). The output includes
/* LINTLIBRARY */
Special comments LINT_EXTERN and LINT_PREPRO (a la "VARARGS") respectively turn on
the "-x" option and copy comment-text to the output (for preprocessing in lint).
Use the comment
/* LINT_EXTERN2 */
to include externs defined in the first level of include-files. Use the comment
/* LINT_SHADOWED */
to cause cproto to put "#undef" directives before each lint library declaration
(i.e., to avoid conflicts with macros that happen to have to have the same name as
the functions, thus causing syntax errors).
Note that these special comments are not supported under VAX/VMS, since there is no equiv-
alent for the "-C" option of cpp with VAX-C.
-c The parameter comments in the prototypes generated by the -f1 and -f2 options are
omitted by default. Use this option to enable the output of these comments.
-m Put a macro around the parameter list of every generated prototype. For example:
int main P_((int argc, char *argv));
Set the name of the macro used to surround prototype parameter lists when option -m
is selected. The default is "P_".
-d Omit the definition of the prototype macro used by the -m option.
Specify the name of the output file (default: standard output).
Specify the name of the error file (default: standard error).
-p Disable promotion of formal parameters in old style function definitions. By
default, parameters of type char or short in old style function definitions are
promoted to type int in the function prototype or converted ANSI C function defini-
tion. Parameters of type float get promoted to double as well.
-q Do not output any error messages when the program cannot read the file specified in
an #include directive.
-s By default, cproto only generates declarations for functions and variables having
global scope. This option will output static declarations as well.
-S Output only static declarations.
-T Copy type definitions from each file. (Definitions in included-files are copied,
unlike the "-l" option).
-v Also output declarations for variables defined in the source.
-x This option causes procedures and variables which are declared "extern" to be
included in the output.
-a Convert function definitions from the old style to the ANSI C style.
-t Convert function definitions from the ANSI C style to the traditional style.
-b Rewrite function definition heads to include both old style and new style declara-
tions separated by a conditional compilation directive. For example, the program
can generate this function definition:
main (int argc, char *argv)
main (argc, argv)
Set the conditional compilation directive to output at the beginning of function
definitions generated by the -b option. The default is
Set the output format for generated prototypes, function definitions, and function
definitions with parameter comments respectively. The format is specified by a tem-
plate in the form
" int f ( a, b )"
but you may replace each space in this string with any number of whitespace charac-
ters. For example, the option
This option is passed through to the preprocessor and is used to define symbols for
use with conditionals such as #ifdef.
This option is passed through to the preprocessor and is used to remove any defini-
tions of this symbol.
This option is passed through to the preprocessor and is used to specify a direc-
tory to search for files that are referenced with #include.
-E cpp Pipe the input files through the specified C preprocessor command when generating
prototypes. By default, the program uses /lib/cpp.
-E 0 Do not run the C preprocessor.
-V Print version information.
The environment variable CPROTO is scanned for a list of options in the same format as the
command line options. Options given on the command line override any corresponding envi-
If an un-tagged struct, union or enum declaration appears in a generated function proto-
type or converted function definition, the content of the declaration between the braces
The program does not pipe the source files through the C preprocessor when it is convert-
ing function definitions. Instead, it tries to handle preprocessor directives and macros
itself and can be confused by tricky macro expansions. The conversion also discards some
comments in the function definition head.
The -v option does not generate declarations for variables defined with the extern speci-
fier. This doesn't strictly conform to the C language standard but this rule was imple-
mented because include files commonly declare variables this way.
When the program encounters an error, it usually outputs the not very descriptive message
"syntax error". (Your configuration may allow the extended error reporting in yyerror.c).
Options that take string arguments only interpret the following character escape
VARARGS comments don't get passed through on systems whose C preprocessors don't support
this (e.g., VAX/VMS, MS-DOS).
modifications to support lint library, type-copying, and port to VAX/VMS.
January 1998 CPROTO(1)