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Updated: Wednesday, February 10, 2021

ocamlopt.opt (1)


ocamlopt.opt - code compiler


ocamlopt [ options ] filename ...

ocamlopt.opt (same options)


OCAMLOPT(1)                 General Commands Manual                OCAMLOPT(1)

       ocamlopt - The Objective Caml native-code compiler

       ocamlopt [ options ] filename ...

       ocamlopt.opt (same options)

       The  Objective  Caml  high-performance native-code compiler ocamlopt(1)
       compiles Caml source files to native code object files and  link  these
       object files to produce standalone executables.

       The ocamlopt(1) command has a command-line interface very close to that
       of ocamlc(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
       ocamlopt(1)  compiler  produces a compiled interface in the file x.cmi.
       The interface produced is identical to that produced  by  the  bytecode
       compiler ocamlc(1).

       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 ocamlopt(1) compiler  pro-
       duces  two  files:  x.o, containing native object code, and x.cmx, con-
       taining 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, ocamlopt(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 ocamlc(1).

       Arguments ending in .cmx are taken to be compiled object  code.   These
       files are linked together, along with the object files obtained by com-
       piling .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:  compila-
       tion 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 ocamlopt  -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 ocamlrun(1) to run.

       ocamlopt.opt is the same compiler as ocamlopt, but compiled with itself
       instead  of  with  the  bytecode  compiler ocamlc(1).  Thus, it behaves
       exactly like ocamlopt, but compiles faster.  ocamlopt.opt is not avail-
       able in all installations of Objective Caml.

       The following command-line options are recognized by ocamlopt(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 must be set with the
              -o option.

              If -cclib or -ccopt options are  passed  on  the  command  line,
              these  options are stored in the resulting .cmxa library.  Then,
              linking with this library automatically adds back the 0  options
              as  if  they  had  been provided on the command line, unless the
              -noautolink option is given.

       -annot Dump detailed information about the  compilation  (types,  bind-
              ings,  tail-calls, etc).  The information for file src.ml is put
              into file src.annot.  In case of a  type  error,  dump  all  the
              information  inferred  by the type-checker before the error. The
              src.annot file can be used with  the  emacs  commands  given  in
              emacs/caml-types.el  to  display  types  and  other  annotations

       -c     Compile only. Suppress the linking  phase  of  the  compilation.
              Source  code  files  are turned into compiled files, but no exe-
              cutable file is produced. This option is useful to compile  mod-
              ules separately.

       -cc ccomp
              Use  ccomp  as the C linker called to build the final executable
              and as the C compiler for compiling .c source files.

       -cclib -llibname
              Pass the -llibname option to the linker. This causes the given C
              library to be linked with the program.

       -ccopt option
              Pass  the  given  option  to  the  C  compiler  and  linker. For
              instance, -ccopt -Ldir 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.

              Print  the  version number of ocamlopt(1) and a detailed summary
              of its configuration, then exit.

       -for-pack module-path
              Generate an object file (.cmx and .o files) that  can  later  be
              included  as a sub-module (with the given access path) of a com-
              pilation unit  constructed  with  -pack.   For  instance,  ocam-
              lopt -for-pack P -c A.ml  will generate a.cmx and a.o files that
              can later be used with ocamlopt -pack -o P.cmx a.cmx.

       -g     Add debugging information  while  compiling  and  linking.  This
              option is required in order to produce stack backtraces when the
              program terminates on an uncaught exception (see ocamlrun(1)).

       -i     Cause the compiler  to  print  all  defined  names  (with  their
              inferred types or their definitions) when compiling an implemen-
              tation (.ml file). No compiled files (.cmo and .cmi  files)  are
              produced.  This can be useful to check the types inferred by the
              compiler. Also, since the output follows the  syntax  of  inter-
              faces,  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.

       -I directory
              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
              library directory.

              If the given directory starts with +, it is  taken  relative  to
              the  standard  library  directory. For instance, -I +labltk adds
              the subdirectory labltk of the standard library  to  the  search

       -inline n
              Set aggressiveness of inlining to n, where n is a positive inte-
              ger. Specifying -inline 0  prevents  all  functions  from  being
              inlined,  except those whose body is smaller than the call site.
              Thus, inlining causes no expansion in  code  size.  The  default
              aggressiveness,  -inline 1,  allows slightly larger functions to
              be inlined, resulting in a slight expansion in code size. Higher
              values  for the -inline option cause larger and larger functions
              to become candidate for inlining, but can result  in  a  serious
              increase in code size.

       -intf filename
              Compile  the  file  filename  as  an interface file, even if its
              extension is not .mli.

       -intf-suffix string
              Recognize file names  ending  with  string  as  interface  files
              (instead of the default .mli).

              Labels  are not ignored in types, labels may be used in applica-
              tions, and labelled parameters can be given in any order.   This
              is the default.

              Force  all  modules  contained  in libraries to be linked in. If
              this flag is not given, unreferenced modules are not linked  in.
              When  building  a  library  (-a flag), setting the -linkall flag
              forces all subsequent links of programs involving  that  library
              to link all the modules contained in the library.

              Do  not  compile  assertion  checks.  Note that the special form
              assert false is always compiled because it is  typed  specially.
              This flag has no effect when linking already-compiled files.

              When  linking  .cmxa libraries, ignore -cclib and -ccopt options
              potentially contained in the libraries (if  these  options  were
              given  when  building  the  libraries).  This can be useful if a
              library contains incorrect specifications of C  libraries  or  C
              options;  in this case, during linking, set -noautolink and pass
              the correct C libraries and options on the command line.

              Allow the compiler to use some optimizations that are valid only
              for code that is never dynlinked.

              Ignore  non-optional  labels  in types. Labels cannot be used in
              applications, and parameter order becomes strict.

       -o exec-file
              Specify the name of the output file produced by the linker.  The
              default  output  name  is a.out, in keeping with the Unix tradi-
              tion. If the -a option is given, specify the name of the library
              produced.  If the -pack option is given, specify the name of the
              packed object file  produced.   If  the  -output-obj  option  is
              given,  specify  the  name  of  the output file produced. If the
              -shared option is given, specify the name of  plugin  file  pro-

              Cause  the  linker to produce a C object file instead of an exe-
              cutable file. This is useful to wrap Caml code as a  C  library,
              callable  from any C program. The name of the output object file
              is camlprog.o by default; it can be  set  with  the  -o  option.
              This   option   can   also   be   used  to  produce  a  compiled
              shared/dynamic library (.so extension).

       -p     Generate extra code to write profile information when  the  pro-
              gram  is executed.  The profile information can then be examined
              with the analysis program gprof(1).  The -p option must be given
              both at compile-time and at link-time.  Linking object files not
              compiled with -p is possible, but results in less  precise  pro-

              See  the  gprof(1)  man page for more information about the pro-

              Full support for gprof(1) is only available  for  certain  plat-
              forms  (currently:  Intel x86/Linux and Alpha/Digital Unix).  On
              other platforms, the -p option will result  in  a  less  precise
              profile (no call graph information, only a time profile).

       -pack  Build an object file (.cmx and .o files) and its associated com-
              piled interface (.cmi) that combines the .cmx object files given
              on  the  command  line, making them appear as sub-modules of the
              output .cmx file.  The name of the  output  .cmx  file  must  be
              given    with    the    -o    option.    For   instance,   ocam-
              lopt -pack -o P.cmx A.cmx B.cmx C.cmx generates  compiled  files
              P.cmx,  P.o and P.cmi describing a compilation unit having three
              sub-modules A, B and C, corresponding to  the  contents  of  the
              object files A.cmx, B.cmx and C.cmx.  These contents can be ref-
              erenced as P.A, P.B and P.C in the remainder of the program.

              The .cmx object files being combined  must  have  been  compiled
              with  the  appropriate  -for-pack option.  In the example above,
              A.cmx, B.cmx and  C.cmx  must  have  been  compiled  with  ocam-
              lopt -for-pack P.

              Multiple  levels  of  packing can be achieved by combining -pack
              with -for-pack.  See The Objective Caml user's  manual,  chapter
              "Native-code compilation" for more details.

       -pp command
              Cause  the  compiler to call the given command as a preprocessor
              for each source file. The output of command is redirected to  an
              intermediate  file,  which is compiled. If there are no compila-
              tion errors, the intermediate file is deleted afterwards.

              Check information path during type-checking, to make  sure  that
              all  types are derived in a principal way. All programs accepted
              in -principal mode are also accepted in default mode with equiv-
              alent types, but different binary signatures.

              Allow   arbitrary  recursive  types  during  type-checking.   By
              default, only recursive types where the recursion  goes  through
              an object type are supported. Note that once you have created an
              interface using this flag, you must use it again for all  depen-

       -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.

              Build a plugin (usually .cmxs) that can  be  dynamically  loaded
              with the Dynlink module. The name of the plugin must be set with
              the -o option. A plugin can include a number of Caml modules and
              libraries,  and  extra  native objects (.o, .a files).  Building
              native plugins is only  supported  for  some  operating  system.
              Under  some systems (currently, only Linux AMD 64), all the Caml
              code linked in a plugin must  have  been  compiled  without  the
              -nodynlink  flag.  Some  constraints might also apply to the way
              the extra native objects have been compiled (under Linux AMD 64,
              they must contain only position-independent code).

              Compile  or link multithreaded programs, in combination with the
              system threads library described in The  Objective  Caml  user's

              Turn  bound  checking  off  for  array  and string accesses (the
              v.(i)ands.[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. Additionally,
              turn off the check for zero divisor in integer division and mod-
              ulus operations.  With -unsafe, an integer division (or modulus)
              by  zero  can  halt  the program or continue with an unspecified
              result instead of raising a Division_by_zero exception.

       -v     Print the version number of the compiler and the location of the
              standard library directory, then exit.

              Print all external commands before they are executed, in partic-
              ular invocations of the assembler, C compiler, and linker.

              Print the version number of the compiler  in  short  form  (e.g.
              "3.11.0"), then exit.

       -w warning-list
              Enable  or  disable  warnings  according  to  the argument warn-
              ing-list.  The argument is a set of letters.   If  a  letter  is
              uppercase, it enables the corresponding warnings; lowercase dis-
              ables the warnings.  The correspondence is the following:

              A   all warnings

              C   start of comments that look like mistakes

              D   use of deprecated features

              E   fragile pattern matchings (matchings that will  remain  com-
              plete  even  if  additional constructors are added to one of the
              variant types matched)

              F   partially applied functions (expressions  whose  result  has
              function type and is ignored)

              L   omission of labels in applications

              M   overriding of methods

              P   missing cases in pattern matchings (i.e. partial matchings)

              S    expressions  in the left-hand side of a sequence that don't
              have type unit (and that are not functions, see F above)

              U   redundant cases in pattern matching (unused cases)

              V   overriding of instance variables

              Y   unused variables that are bound with  let or as,  and  don't
              start with an underscore (_) character

              Z   all other cases of unused variables that don't start with an
              underscore (_) character

              X   warnings that don't fit in the above categories (except A)

              The default setting is -w Aelz,  enabling  all  warnings  except
              fragile  pattern matchings, omitted labels, and innocuous unused
              variables.  Note that warnings F and S are not always triggered,
              depending on the internals of the type checker.

       -warn-error warning-list
              Turn  the  warnings  indicated in the argument warning-list into
              errors.  The compiler will stop with an error when one of  these
              warnings  is  emitted.  The warning-list has the same meaning as
              for the "-w" option: an uppercase  character  turns  the  corre-
              sponding  warning into an error, a lowercase character leaves it
              as a warning.  The default setting is -warn-error a (none of the
              warnings is treated as an error).

       -where Print the location of the standard library, then exit.

       - file Process  file  as a file name, even if it starts with a dash (-)

       -help or --help
              Display a short usage summary and exit.

       The IA32 code generator (Intel Pentium, AMD Athlon) supports  the  fol-
       lowing additional option:

              Use  the IA32 instructions to compute trigonometric and exponen-
              tial functions, instead of  calling  the  corresponding  library
              routines.   The  functions  affected are: atan, atan2, cos, log,
              log10, sin, sqrt and tan.  The resulting code runs  faster,  but
              the range of supported arguments and the precision of the result
              can be reduced.  In particular,  trigonometric  operations  cos,
              sin, tan have their range reduced to [-2^64, 2^64].

       The  AMD64  code  generator  (64-bit  versions of Intel Pentium and AMD
       Athlon) supports the following additional options:

       -fPIC  Generate  position-independent  machine  code.   This   is   the

              Generate position-dependent machine code.

       The Sparc code generator supports the following additional options:

              Generate SPARC version 8 code.

              Generate SPARC version 9 code.

       The  default is to generate code for SPARC version 7, which runs on all
       SPARC processors.

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

       |Availability   | runtime/ocaml    |
       |Stability      | Volatile         |
       The Objective Caml user's manual, chapter "Native-code compilation".

       This    software    was    built    from    source     available     at
       https://github.com/oracle/solaris-userland.    The  original  community
       source     was     downloaded      from       http://caml.inria.fr/dis-

       Further information about this software can be found on the open source
       community website at http://www.ocaml.org.