cppo(1) lightweight cpp-like preprocessor for OCaml


cppo [Options...] files...


cppo is the equivalent of the C preprocessor for OCaml. It permits the definition and expansion of simple (in comparison with camlp4) macros and file inclusion. cppo supports functional macros, conditionals, boolean and arithmetic expressions, stringification, and calling different, external preprocessors. For a precise description of the features, see /usr/share/doc/cppo/README.gz.


define IDENT
undefine IDENT
add DIR to the search path for included files
write output to FILE
Identify and preserve camlp4 quotations
Output line directives pointing to the exact source location of each token, including those coming from the body of macro definitions. This behavior is off by default.
Do not output any line directive other than those found in the input (overrides -s).
print version and exit
Define a custom preprocessor target section starting with:

#ext "NAME"

and ending with:


NAME must be a lowercase identifier of the form [a-z][A-Za-z0-9_]*

CMD_TEMPLATE is a command template supporting the following special sequences:

%F file name (unescaped; beware of potential scripting attacks)
%B number of the first line
%E number of the last line
%% a single percent sign

The filename, the first line number and the last line number are available to the external preprocessor via the environment variables CPPO_FILE, CPPO_FIRST_LINE, CPPO_LAST_LINE.

The command is expected to read from stdin and to write to stdout.

-help | --help
Display options and exit


This manual page was written by Sylvain Le Gall <gildo[email protected]> and Hendrik Tews <[email protected]>, specifically for the Debian project (and may be used by others).