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msgcpp - C language message catalog preprocessor


msgcpp [-ACEHMPVX] [-D name[=value]] [-I directory] [-U name]
[-T[length]] [-Y directory] [input [output] ]


msgcpp is a C language message catalog preprocessor. It accepts cpp(1)
style options and arguments. msgcpp preprocesses an input C source file
and emits keyed lines to the output, usually for further processing by
msgcc(1). msgcc output is in the gencat(1) syntax. Candidate message
text is determined by arguments to the last <error.h> and <option.h>
functions. The msgcpp keyed output lines are:

cmd command
command is a candidate for --??keys option string
generation. This is triggered by b_command(int argc,
in the input.

def name string
name is a candidate variable with string value string.

str string
string should be entered into the catalog.

var name
If def name occurs then its string value should be
entered into the catalog.

The input source file is preprocessed with the pp:allpossible option on.
This enables non-C semantics. All source should first be compiled error-
free with a real compiler before running msgcpp. The following changes
are enabled for the top level files. Included file behavior is not

1. All #if, #ifdef and #ifndef branches are enabled.

2. The first definition for a macro is retained, even when
subsequent #define statements would normally redefine the
macro. #undef must be used to redefine a macro.

3. Macro calls with an improper number of arguments are silently

4. #include on non-existent headers are silently ignored.

5. Invalid C source characters are silently ignored.

msgcat.h is included if it exists. This file may contain macro
definitions for functions that translate string arguments. If foo is a
function that translates its string arguments then include the line
#define foo _TRANSLATE_ in msgcat.h, or specify the option
-Dfoo=_TRANSLATE_. If bar is a function that translates string arguments
if the first argument is stderr, then use either #define bar _STDIO_ or

The macro _BLD_msgcat is defined to be 1. As an alternative to msgcat.h,
_TRANSLATE_ definitions could be placed inside #ifdef _BLD_msgcat ...


The following options are supported:

Enter the assertion using #assert for system V

Pass comments to the output.

Comments are omitted by default.

Define the macro name to have value. This is the
only portable way to pass options through cc to

o If =value is omitted, value is
assumed to be 1 .

o If name begins with :, then it is
interpreted as a libpp #pragma pp:

o If name begins with %, it is
interpreted as a libpp # directive

o If name begins with a - or a +, it is
interpreted as a libpp option.

- turns the option on, + turns it

o Most options have a #pragma
counterpart that is listed with the
option definition.


Preprocess for K&R C compatibility.

pp:debug level level

Set the debug trace level.

Specify level as a number greater than or
equal to 0. Higher levels produce more
output. Levels higher than 3 can only be
enabled in the -g compiled versions.


Set the main input file name to name. This
only affects the error messages and the line
sync output.


All directories are hosted. Compatibility
warning messages from the hosted directory
headers are suppressed.


All directories contain C headers. This
option is only used only with -D-+.


Enable the non-standard name=value macro
argument mode.

pp:lineid [id]

Set the line sync directive id to id. If id
is not specified, set to null.


Disable multiple include detection.


Enable the non-standard passthrough mode.
This can be useful for processing non-C


Dump macro definitions to the output so that
the output may be passed through cpp again.
This is used for generating precompiled


Enable the transition preprocessing mode.
This is used for compilers that cannot make
up their semantics between K&R and ISO C.


Enable strict preprocessing semantics and
warnings. This works with any mode
(compatibility, transition, or the default

pp:test test

Enable implementation specific test code
according to test.


Enable pedantic warnings in non-hosted


Preprocess for the cc compiler, which must
be an executable path or an executable on


Enable pool mode.


List canonicalized #define statements for
non-predefined macros in the output.


List canonicalized #define statements for
all macros. All other output is disabled.


Preprocess for the C++ dialect.

Ignored; for compatibility with very old

Emit #include file paths on the standard error,
one per line, indented to show nesting.

Append directory to the list of directories
searched for #include files.

If directory is -:

1. -I directories before -I- are
searched only for "..." include files

2. -I directories after -I- are searched
for "..." and <"..."> include files

3. the directory . is searched only if
it is explicitly specified by an -I

pp:cdir directory

Mark directory as a C header directory. This
option is used with pp:plusplus.


Read the default probe definitions from
file, or ignore the default definitions if
file is omitted.

pp:hostdir directory

Mark directory as a hosted directory.
Headers from hosted directories have
compatibility warnings disabled.

pp:ignore header

Add header to the list of ignored headers.


file contains a sequence of header [= "map"
] lines, where header is either <name> or
"name", and "map" is an explicit binding for
header. header is ignored if = "map" is


Include file but do not emit text or line


Add directory to the default standard
include directory list.


Include file and emit text to the output
file. The option value can be omitted.

Generate make(1S) dependencies. This option is
not needed with nmake.

The -M option can be followed by optional flags
to change the dependency output styles.

The following optional flags are supported:

Generate dependencies in a separate .d
file. Preprocessed output is still written
to output, or the standard output if output
is omitted.

Also generate missing dependencies.

Only generate local header dependencies.
Hosted headers are omitted. Hosted headers
are determined by the -I-H option and the
--pp:hosted and pp:hostdir pragmas. No
special distinction is made between the ""
and <> include styles.

Emit line syncs.

Line sync is turned on by default. -P means

If not gcc, truncate identifiers to length
characters for compatibility with old AT&T

Remove the definition for the macro name.

Emit the libpp version.

Enable name=value macro arguments for easel

Add directory to the list searched for #include
<...> files.


The following operands are supported:

Specifies C source file to preprocess.

Specifies output file.


Successful completion.

An error occurred.


Example 1: Using msgcpp to Extract Localizable Strings

The following example uses msgcpp to extract localizable strings from the
file hello.c, marked using the ERROR_dictionary(), and writes them to the
file hello.mso:

example% cat hello.c

#include <stdio.h>
#include <stdlib.h>

* dummy macro to avoid including
* libast headers
#define ERROR_dictionary(x) x

int main(int ac, char *av[])
puts( ERROR_dictionary("hello world") );
puts( ERROR_dictionary("hello all") );
return( EXIT_SUCCESS );

example% msgcpp -D__STDC__ -D__i386 hello.c hello.mso

example% cat hello.mso
str "hello world"
str "hello all"


Glenn Fowler,


See attributes(7) for descriptions of the following attributes:

|Interface Stability | Volatile |


cpp(1), gencat(1), msgcc(1), msgcvt(1), msggen(1), make(1S),

Kernighan, Brian W. and Ritchie, Dennis M., The C Programming Language,
Prentice Hall, 1988.

October 9, 2007 MSGCPP(1)