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       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,  the  ocamlopt(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,  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
       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 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
       available 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  0options
              as  if  they  had  been provided on the command line, unless the
              -noautolink option is given.

       -annot Dump  detailed  information  about   the   compilation   (types,
              bindings,  tail-calls, etc).  The information for file 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
              executable file is produced. This option is  useful  to  compile
              modules 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
              compilation  unit  constructed  with   -pack.    For   instance,
              ocamlopt -for-pack P -c  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
              implementation (.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  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.

       -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
              integer. 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
              applications, 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
              tradition. 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

              Cause  the  linker  to  produce  a  C  object file instead of an
              executable 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
              program  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 profiling.

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

              Full  support  for  gprof(1)  is  only  available  for   certain
              platforms  (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
              compiled 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,
              ocamlopt -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
              referenced 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
              ocamlopt -for-pack P.

              Multiple levels of packing can be achieved  by  combining  -pack
              with  -for-pack.   See The Objective Caml users 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
              compilation 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
              equivalent 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

       -S     Keep  the  assembly  code  produced  during the compilation. The
              assembly code for the source file 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 users

              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
              modulus  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

       -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
              particular 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
              warning-list.  The argument is a set of letters.  If a letter is
              uppercase, it  enables  the  corresponding  warnings;  lowercase
              disables 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
              complete 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
              corresponding 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
       following additional option:

              Use  the  IA32  instructions  to   compute   trigonometric   and
              exponential  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.


       The Objective Caml users manual, chapter "Native-code compilation".