1OCAMLOPT(1) General Commands Manual OCAMLOPT(1)
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6 ocamlopt - The Objective Caml native-code compiler
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11 ocamlopt [ -acivS ] [ -cclib libname ] [ -ccopt option ] [ -compact ] [
12 -unsafe ] [ -o exec-file ] [ -I lib-dir ] filename ...
13 ocamlopt.opt (same options)
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18 The Objective Caml high-performance native-code compiler ocamlopt(1)
19 compiles Caml source files to native code object files and link these
20 object files to produce standalone executables.
21 The ocamlopt(1) command has a command-line interface very close to that
23 of ocamlc(1). It accepts the same types of arguments and processes
24 them sequentially:
25 Arguments ending in .mli are taken to be source files for compilation
27 unit interfaces. Interfaces specify the names exported by compilation
28 units: they declare value names with their types, define public data
29 types, declare abstract data types, and so on. From the file x.mli, the
30 ocamlopt(1) compiler produces a compiled interface in the file x.cmi.
31 The interface produced is identical to that produced by the bytecode
32 compiler ocamlc(1).
33 Arguments ending in .ml are taken to be source files for compilation
35 unit implementations. Implementations provide definitions for the names
36 exported by the unit, and also contain expressions to be evaluated for
37 their side-effects. From the file x.ml, the ocamlopt(1) compiler pro‐
38 duces two files: x.o, containing native object code, and x.cmx, con‐
39 taining extra information for linking and optimization of the clients
40 of the unit. The compiled implementation should always be referred to
41 under the name x.cmx (when given a .o file, ocamlopt(1) assumes that it
42 contains code compiled from C, not from Caml).
43 The implementation is checked against the interface file x.mli (if it
45 exists) as described in the manual for ocamlc(1).
46 Arguments ending in .cmx are taken to be compiled object code. These
48 files are linked together, along with the object files obtained by com‐
49 piling .ml arguments (if any), and the Caml Light standard library, to
50 produce a native-code executable program. The order in which .cmx and
51 .ml arguments are presented on the command line is relevant: compila‐
52 tion units are initialized in that order at run-time, and it is a link-
53 time error to use a component of a unit before having initialized it.
54 Hence, a given x.cmx file must come before all .cmx files that refer to
55 the unit x.
56 Arguments ending in .cmxa are taken to be libraries of object code.
58 Such a library packs in two files lib.cmxa and lib.a a set of object
59 files (.cmx/.o files). Libraries are build with ocamlopt -a (see the
60 description of the -a option below). The object files contained in the
61 library are linked as regular .cmx files (see above), in the order
62 specified when the library was built. The only difference is that if an
63 object file contained in a library is not referenced anywhere in the
64 program, then it is not linked in.
65 Arguments ending in .c are passed to the C compiler, which generates a
67 .o object file. This object file is linked with the program.
68 Arguments ending in .o or .a are assumed to be C object files and
70 libraries. They are linked with the program.
71 The output of the linking phase is a regular Unix executable file. It
73 does not need ocamlrun(1) to run.
74 ocamlopt.opt is the same compiler as ocamlopt, but compiled with itself
76 instead of with the bytecode compiler ocamlc(1). Thus, it behaves
77 exactly like ocamlopt, but compiles faster. ocamlopt.opt is not avail‐
78 able in all installations of Objective Caml.
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82 The following command-line options are recognized by ocamlopt(1).
83 -a Build a library (.cmxa/.a file) with the object files (.cmx/.o
86 files) given on the command line, instead of linking them into
87 an executable file. The name of the library can be set with the
88 -o option. The default name is library.cmxa.
89 -c Compile only. Suppress the linking phase of the compilation.
92 Source code files are turned into compiled files, but no exe‐
93 cutable file is produced. This option is useful to compile mod‐
94 ules separately.
95 -cclib -llibname
98 Pass the -llibname option to the linker. This causes the given C
99 library to be linked with the program.
100 -ccopt option
103 Pass the given option to the C compiler and linker. For
104 instance, -ccopt -L dir causes the C linker to search for C
105 libraries in directory dir.
106 -compact
109 Optimize the produced code for space rather than for time. This
110 results in smaller but slightly slower programs. The default is
111 to optimize for speed.
112 -i Cause the compiler to print all defined names (with their
115 inferred types or their definitions) when compiling an implemen‐
116 tation (.ml file). This can be useful to check the types
117 inferred by the compiler. Also, since the output follows the
118 syntax of interfaces, it can help in writing an explicit inter‐
119 face (.mli file) for a file: just redirect the standard output
120 of the compiler to a .mli file, and edit that file to remove all
121 declarations of unexported names.
122 -I directory
125 Add the given directory to the list of directories searched for
126 compiled interface files (.cmi) and compiled object code files
127 (.cmo). By default, the current directory is searched first,
128 then the standard library directory. Directories added with -I
129 are searched after the current directory, in the order in which
130 they were given on the command line, but before the standard
131 library directory.
132 -o exec-file
135 Specify the name of the output file produced by the linker. The
136 default output name is a.out, in keeping with the Unix tradi‐
137 tion. If the -a option is given, specify the name of the library
138 produced.
139 -S Keep the assembly code produced during the compilation. The
142 assembly code for the source file x.ml is saved in the file x.s.
143 -v Print the version number of the compiler.
146 -unsafe
149 Turn bound checking off on array and string accesses (the v.(i)
150 and s.[i] constructs). Programs compiled with -unsafe are there‐
151 fore faster, but unsafe: anything can happen if the program
152 accesses an array or string outside of its bounds.
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156 ocamlc(1).
157 The Objective Caml user's manual, chapter "Native-code compilation".
158 OCAMLOPT(1)