jocamlopt - The JoCaml native-code compiler
jocamlopt [ -acivS ] [ -cclib libname ] [ -ccopt option ] [ -compact ]
[ -unsafe ] [ -o exec-file ] [ -I lib-dir ] filename ...
jocamlopt.opt (same options)
The JoCaml high-performance native-code compiler jocamlopt(1) compiles
Caml source files to native code object files and link these object
files to produce standalone executables.
The jocamlopt(1) command has a command-line interface very close to
that of jocamlc(1). It accepts the same types of arguments and
processes them sequentially:
Arguments ending in .mli are taken to be source files for compilation
unit interfaces. Interfaces specify the names exported by compilation
units: they declare value names with their types, define public data
types, declare abstract data types, and so on. From the file x.mli, the
jocamlopt(1) compiler produces a compiled interface in the file x.cmi.
The interface produced is identical to that produced by the bytecode
Arguments ending in .ml are taken to be source files for compilation
unit implementations. Implementations provide definitions for the names
exported by the unit, and also contain expressions to be evaluated for
their side-effects. From the file x.ml, the jocamlopt(1) compiler
produces two files: x.o, containing native object code, and x.cmx,
containing extra information for linking and optimization of the
clients of the unit. The compiled implementation should always be
referred to under the name x.cmx (when given a .o file, jocamlopt(1)
assumes that it contains code compiled from C, not from Caml).
The implementation is checked against the interface file x.mli (if it
exists) as described in the manual for jocamlc(1).
Arguments ending in .cmx are taken to be compiled object code. These
files are linked together, along with the object files obtained by
compiling .ml arguments (if any), and the Caml Light standard library,
to produce a native-code executable program. The order in which .cmx
and .ml arguments are presented on the command line is relevant:
compilation units are initialized in that order at run-time, and it is
a link-time error to use a component of a unit before having
initialized it. Hence, a given x.cmx file must come before all .cmx
files that refer to the unit x.
Arguments ending in .cmxa are taken to be libraries of object code.
Such a library packs in two files lib.cmxa and lib.a a set of object
files (.cmx/.o files). Libraries are build with jocamlopt -a (see the
description of the -a option below). The object files contained in the
library are linked as regular .cmx files (see above), in the order
specified when the library was built. The only difference is that if an
object file contained in a library is not referenced anywhere in the
program, then it is not linked in.
Arguments ending in .c are passed to the C compiler, which generates a
.o object file. This object file is linked with the program.
Arguments ending in .o or .a are assumed to be C object files and
libraries. They are linked with the program.
The output of the linking phase is a regular Unix executable file. It
does not need jocamlrun(1) to run.
jocamlopt.opt is the same compiler as jocamlopt, but compiled with
itself instead of with the bytecode compiler jocamlc(1). Thus, it
behaves exactly like jocamlopt, but compiles faster. jocamlopt.opt is
not available in all installations of JoCaml.
The following command-line options are recognized by jocamlopt(1).
-a Build a library (.cmxa/.a file) with the object files (.cmx/.o
files) given on the command line, instead of linking them into
an executable file. The name of the library can be set with the
-o option. The default name is library.cmxa.
-c Compile only. Suppress the linking phase of the compilation.
Source code files are turned into compiled files, but no
executable file is produced. This option is useful to compile
Pass the -llibname option to the linker. This causes the given C
library to be linked with the program.
Pass the given option to the C compiler and linker. For
instance, -ccopt -L dir causes the C linker to search for C
libraries in directory dir.
Optimize the produced code for space rather than for time. This
results in smaller but slightly slower programs. The default is
to optimize for speed.
-i Cause the compiler to print all defined names (with their
inferred types or their definitions) when compiling an
implementation (.ml file). This can be useful to check the types
inferred by the compiler. Also, since the output follows the
syntax of interfaces, it can help in writing an explicit
interface (.mli file) for a file: just redirect the standard
output of the compiler to a .mli file, and edit that file to
remove all declarations of unexported names.
Add the given directory to the list of directories searched for
compiled interface files (.cmi) and compiled object code files
(.cmo). By default, the current directory is searched first,
then the standard library directory. Directories added with -I
are searched after the current directory, in the order in which
they were given on the command line, but before the standard
Specify the name of the output file produced by the linker. The
default output name is a.out, in keeping with the Unix
tradition. If the -a option is given, specify the name of the
-S Keep the assembly code produced during the compilation. The
assembly code for the source file x.ml is saved in the file x.s.
-v Print the version number of the compiler.
Turn bound checking off on array and string accesses (the v.(i)
and s.[i] constructs). Programs compiled with -unsafe are
therefore faster, but unsafe: anything can happen if the program
accesses an array or string outside of its bounds.
The Objective Caml users manual, chapter "Native-code compilation".