Provided by: ocaml_4.13.1-3ubuntu1_amd64 bug


       ocamlc - The OCaml bytecode compiler


       ocamlc [ options ] filename ...

       ocamlc.opt [ options ] filename ...


       The OCaml bytecode compiler ocamlc(1) compiles OCaml source files to bytecode object files
       and links these object files to  produce  standalone  bytecode  executable  files.   These
       executable files are then run by the bytecode interpreter ocamlrun(1).

       The ocamlc(1) command has a command-line interface similar to the one of most C compilers.
       It accepts several types of arguments and processes them sequentially, after  all  options
       have been processed:

       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 ocamlc(1) compiler produces a compiled interface in the file x.cmi.

       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  ocamlc(1)
       compiler produces compiled object bytecode in the file x.cmo.

       If  the  interface  file  x.mli  exists,  the  implementation is checked against the
       corresponding compiled interface x.cmi, which is assumed to exist. If no  interface  x.mli
       is  provided, the compilation of produces a compiled interface file x.cmi in addition
       to the compiled object code file  x.cmo.   The  file  x.cmi  produced  corresponds  to  an
       interface that exports everything that is defined in the implementation

       Arguments ending in .cmo are taken to be compiled object bytecode.  These files are linked
       together, along with the object files obtained by compiling .ml arguments  (if  any),  and
       the OCaml standard library, to produce a standalone executable program. The order in which
       .cmo 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.cmo file must  come  before  all  .cmo
       files that refer to the unit x.

       Arguments  ending  in  .cma  are  taken  to be libraries of object bytecode.  A library of
       object bytecode packs in a single file a  set  of  object  bytecode  files  (.cmo  files).
       Libraries  are  built  with  ocamlc -a  (see  the description of the -a option below). The
       object files contained in the library are linked as regular .cmo files (see above), in the
       order  specified  when  the  .cma file 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  if  the  -custom  flag  is  set  (see  the
       description of -custom below).

       Arguments  ending  in  .o  or  .a are assumed to be C object files and libraries. They are
       passed to the C linker when linking in  -custom  mode  (see  the  description  of  -custom

       Arguments ending in .so are assumed to be C shared libraries (DLLs).  During linking, they
       are searched for external C functions referenced from the OCaml code, and their names  are
       written  in the generated bytecode executable.  The run-time system ocamlrun(1) then loads
       them dynamically at program start-up time.

       The output of the linking phase is  a  file  containing  compiled  bytecode  that  can  be
       executed  by  the OCaml bytecode interpreter: the command ocamlrun(1).  If caml.out is the
       name  of  the  file  produced  by  the  linking  phase,  the  command  ocamlrun   caml.out
       arg1  arg2 ... argn  executes  the  compiled  code  contained  in  caml.out, passing it as
       arguments the character strings arg1 to argn.  (See ocamlrun(1) for more details.)

       On most systems, the file produced by the linking  phase  can  be  run  directly,  as  in:
       ./caml.out  arg1  arg2 ... argn.   The  produced  file  has the executable bit set, and it
       manages to launch the bytecode interpreter by itself.

       ocamlc.opt is the same compiler as ocamlc, but  compiled  with  the  native-code  compiler
       ocamlopt(1).   Thus,  it behaves exactly like ocamlc, but compiles faster.  ocamlc.opt may
       not be available in all installations of OCaml.


       The following command-line options are recognized by ocamlc(1).

       -a     Build a library (.cma file) with the object files (.cmo 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 -custom, -cclib or -ccopt options are passed on the command line, these  options
              are  stored  in  the  resulting  .cma  library.   Then,  linking  with this library
              automatically adds back the -custom, -cclib and -ccopt options as if they had  been
              provided on the command line, unless the -noautolink option is given. Additionally,
              a substring $CAMLORIGIN inside a  -ccopt options will be replaced by the full  path
              to  the  .cma library, excluding the filename.  -absname Show absolute filenames in
              error messages.

       -annot Deprecated since 4.11. Please use -bin-annot instead.

              Dump detailed information about the compilation (types, bindings, tail-calls,  etc)
              in  binary  format.  The  information for file is put into file src.cmt.  In
              case of a type error, dump all the information inferred by the type-checker  before
              the  error.   The  annotation files produced by -bin-annot contain more information
              and are much more compact than the files produced by -annot.

       -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 when linking in "custom runtime" mode  (see  the  -custom
              option) and as the C compiler for compiling .c source files.

       -cclib -llibname
              Pass  the  -llibname  option  to the C linker when linking in "custom runtime" mode
              (see the -custom option). This causes the given C library to  be  linked  with  the

       -ccopt option
              Pass  the  given  option  to  the  C  compiler  and linker, when linking in "custom
              runtime" mode (see the -custom option). For instance,  -ccopt -Ldir  causes  the  C
              linker to search for C libraries in directory dir.

       -color mode
              Enable  or  disable  colors  in compiler messages (especially warnings and errors).
              The following modes are supported:

              auto use heuristics to enable colors only if the output  supports  them  (an  ANSI-
              compatible tty terminal);

              always enable colors unconditionally;

              never disable color output.

              The  default  setting  is  auto,  and  the current heuristic checks that the "TERM"
              environment variable exists and is not empty or  "dumb",  and  that  isatty(stderr)

              The environment variable "OCAML_COLOR" is considered if -color is not provided. Its
              values are auto/always/never as above.

       -error-style mode
              Control the way error messages and warnings are printed.  The following  modes  are

              short only print the error and its location;

              contextual  like "short", but also display the source code snippet corresponding to
              the location of the error.

              The default setting is contextual.

              The environment variable "OCAML_ERROR_STYLE" is considered if -error-style  is  not
              provided. Its values are short/contextual as above.

              Check that the generated bytecode executable can run on 32-bit platforms and signal
              an error if it cannot. This is useful when compiling bytecode on a 64-bit machine.

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

              Print  the value of a specific configuration variable from the -config output, then
              exit. If the variable does not exist, the exit code is non-zero.

              Link in "custom runtime" mode. In the default linking  mode,  the  linker  produces
              bytecode  that  is  intended  to  be  executed  with  the  shared  runtime  system,
              ocamlrun(1).  In the custom runtime mode, the linker produces an output  file  that
              contains  both  the  runtime system and the bytecode for the program. The resulting
              file is larger, but it can be executed directly, even if the ocamlrun(1) command is
              not  installed. Moreover, the "custom runtime" mode enables linking OCaml code with
              user-defined C functions.

              Never use the strip(1) command on  executables  produced  by  ocamlc -custom,  this
              would remove the bytecode part of the executable.

              Security  warning:  never set the "setuid" or "setgid" bits on executables produced
              by ocamlc -custom, this would make them vulnerable to attacks.

       -depend ocamldep-args
              Compute dependencies, as ocamldep would do.

       -dllib -llibname
              Arrange for the C shared library to be loaded dynamically by the run-
              time system ocamlrun(1) at program start-up time.

       -dllpath dir
              Adds  the  directory  dir  to  the run-time search path for shared C libraries.  At
              link-time, shared libraries are searched in  the  standard  search  path  (the  one
              corresponding  to  the  -I  option).   The -dllpath option simply stores dir in the
              produced executable file, where ocamlrun(1) can find it and use it.

       -for-pack module-path
              Generate an object file (.cmo file) that can later  be  included  as  a  sub-module
              (with  the  given  access  path) of a compilation unit constructed with -pack.  For
              instance, ocamlc -for-pack P -c will generate a.cmo that  can  later  be  used
              with  ocamlc  -pack  -o  P.cmo  a.cmo.   Note: you can still pack a module that was
              compiled without -for-pack but in this case exceptions will  be  printed  with  the
              wrong names.

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

       -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), compiled object code files (.cmo), libraries (.cma), and C  libraries
              specified with -cclib -lxxx .  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. See also option -nostdlib.

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

       -impl filename
              Compile the file filename as an implementation file, even if its extension  is  not

       -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

              Keep documentation strings in generated .cmi files.

              Keep locations in generated .cmi files.

              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 (option -a),
              setting  the -linkall option forces all subsequent links of programs involving that
              library to link all the modules contained in the library.  When compiling a  module
              (option  -c),  setting  the -linkall option ensures that this module will always be
              linked if it is put in a library and this library is linked.

              Build a custom runtime system (in the file specified by  option  -o)  incorporating
              the  C  object  files and libraries given on the command line.  This custom runtime
              system can be used later to execute bytecode executables produced with  the  option
              ocamlc -use-runtime runtime-name.

              Set  number  of  rows  of  context  used during pattern matching compilation. Lower
              values cause faster compilation, but less optimized code. The default value is 32.

              Do not record dependencies for module aliases.

              Deactivates the applicative behaviour of functors. With this option,  each  functor
              application  generates  new types in its result and applying the same functor twice
              to the same argument yields two incompatible structures.

              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 .cma libraries, ignore -custom, -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.

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

              Do  not automatically add the standard library directory to the list of directories
              searched for compiled interface files (.cmi), compiled object  code  files  (.cmo),
              libraries  (.cma),  and  C libraries specified with -cclib -lxxx .  See also option

       -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 or -output-complete-obj
              option is given, specify the name of the output file produced.  This  can  also  be
              used  when compiling an interface or implementation file, without linking, in which
              case it sets the name of the cmi or cmo file, and also sets the module name to  the
              file name up to the first dot.

              Interface file compiled with this option are marked so that other compilation units
              depending on it will not  rely  on  any  implementation  details  of  the  compiled
              implementation.  The  native compiler will not access the .cmx file of this unit --
              nor warn if it is absent. This can improve speed of compilation, for  both  initial
              and incremental builds, at the expense of performance of the generated code.

       -open module
              Opens  the given module before processing the interface or implementation files. If
              several -open options are given, they are  processed  in  order,  just  as  if  the
              statements open! module1;; ... open! moduleN;; were added at the top of each file.

              Cause  the linker to produce a C object file instead of a bytecode executable file.
              This is useful to wrap OCaml code as a C library, callable from any C program.  The
              name of the output object file must be set with the -o option. This option can also
              be used to produce a C source file (.c  extension)  or  a  compiled  shared/dynamic
              library (.so extension).

              Same  as  -output-obj  except  when  creating  an object file where it includes the
              runtime and autolink libraries.

       -pack  Build a bytecode object file (.cmo file)  and  its  associated  compiled  interface
              (.cmi) that combines the object files given on the command line, making them appear
              as sub-modules of the output .cmo file.  The name of the output .cmo file  must  be
              given  with  the  -o option.  For instance, ocamlc -pack -o p.cmo a.cmo b.cmo c.cmo
              generates compiled files p.cmo and p.cmi describing a compilation unit having three
              sub-modules  A,  B  and C, corresponding to the contents of the object files a.cmo,
              b.cmo and c.cmo.  These contents can be referenced as  P.A,  P.B  and  P.C  in  the
              remainder of the program.

       -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. The name of this file is built from the basename  of  the  source  file
              with the extension .ppi for an interface (.mli) file and .ppo for an implementation
              (.ml) file.

       -ppx command
              After parsing, pipe the abstract syntax tree through the preprocessor command.  The
              module Ast_mapper(3) implements the external interface of a preprocessor.

              Check  information  path  during  type-checking,  to  make  sure that all types are
              derived in a principal way.   When  using  labelled  arguments  and/or  polymorphic
              methods,  this  flag  is required to ensure future versions of the compiler will be
              able to infer types correctly, even if internal algorithms  change.   All  programs
              accepted  in  -principal mode are also accepted in the default mode with equivalent
              types, but different binary signatures, and this may slow down type  checking;  yet
              it is a good idea to use it once before publishing source code.

              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

       -runtime-variant suffix
              Add suffix to the name of the runtime library that will be used by the program.  If
              OCaml  was  configured  with  option  -with-debug-runtime,  then  the  d  suffix is
              supported and gives a debug version of the runtime.

       -stop-after pass
              Stop compilation after the given compilation pass. The currently  supported  passes
              are: parsing, typing.

              Enforce the separation between types string and bytes, thereby making strings read-
              only. This is the default.

              When a type is visible under  several  module-paths,  use  the  shortest  one  when
              printing the type's name in inferred interfaces and error and warning messages.

              Force the left-hand part of each sequence to have type unit.

              When  a  type  is  unboxable  (i.e.  a  record with a single argument or a concrete
              datatype with a single constructor of one  argument)  it  will  be  unboxed  unless
              annotated with [@@ocaml.boxed].

              When a type is unboxable  it will be boxed unless annotated with [@@ocaml.unboxed].
              This is the default.

              Turn  bound  checking  off  for  array  and  string  accesses  (the   v.(i)ands.[i]
              constructs).  Programs  compiled  with  -unsafe  are therefore slightly faster, but
              unsafe: anything can happen if the program accesses an array or string  outside  of
              its bounds.

              Identify  the  types  string and bytes,  thereby  making strings writable.  This is
              intended for compatibility with old source code and should not  be  used  with  new

       -use-runtime runtime-name
              Generate  a  bytecode  executable  file  that can be executed on the custom runtime
              system runtime-name, built earlier with ocamlc -make-runtime runtime-name.

       -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 C compiler and linker in -custom mode.  Useful to debug C library problems.

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

       -w warning-list
              Enable,  disable,  or  mark  as  fatal  the  warnings  specified  by  the  argument

              Each  warning  can  be  enabled or disabled,  and each warning can be fatal or non-
              fatal.  If a warning is disabled, it isn't displayed and doesn't affect compilation
              in  any  way  (even  if  it  is  fatal).   If a warning is enabled, it is displayed
              normally by the compiler whenever the source code triggers it.  If  it  is  enabled
              and fatal, the compiler will also stop with an error after displaying it.

              The  warning-list  argument is a sequence of warning specifiers, with no separators
              between them.  A warning specifier is one of the following:

              +num   Enable warning number num.

              -num   Disable warning number num.

              @num   Enable and mark as fatal warning number num.

              +num1..num2   Enable all warnings between num1 and num2 (inclusive).

              -num1..num2   Disable all warnings between num1 and num2 (inclusive).

              @num1..num2   Enable  and  mark  as  fatal  all  warnings  between  num1  and  num2

              +letter    Enable  the  set of warnings corresponding to letter.  The letter may be
              uppercase or lowercase.

              -letter   Disable the set of warnings corresponding to letter.  The letter  may  be
              uppercase or lowercase.

              @letter    Enable  and  mark  as fatal the set of warnings corresponding to letter.
              The letter may be uppercase or lowercase.

              uppercase-letter   Enable the set of warnings corresponding to uppercase-letter.

              lowercase-letter   Disable the set of warnings corresponding to lowercase-letter.

              The warning numbers are as follows.

              1    Suspicious-looking start-of-comment mark.

              2    Suspicious-looking end-of-comment mark.

              3    Deprecated feature.

              4     Fragile  pattern  matching:  matching  that  will  remain  complete  even  if
              additional constructors are added to one of the variant types matched.

              5     Partially  applied function: expression whose result has function type and is

              6    Label omitted in function application.

              7    Method overridden without using the "method!" keyword.

              8    Partial match: missing cases in pattern-matching.

              9    Missing fields in a record pattern.

              10   Expression on the left-hand side of a sequence that  doesn't  have  type  unit
              (and that is not a function, see warning number 5).

              11   Redundant case in a pattern matching (unused match case).

              12   Redundant sub-pattern in a pattern-matching.

              13   Override of an instance variable.

              14   Illegal backslash escape in a string constant.

              15   Private method made public implicitly.

              16   Unerasable optional argument.

              17   Undeclared virtual method.

              18   Non-principal type.

              19   Type without principality.

              20   Unused function argument.

              21   Non-returning statement.

              22   Preprocessor warning.

              23   Useless record with clause.

              24   Bad module name: the source file name is not a valid OCaml module name.

              25   Deprecated: now part of warning 8.

              26    Suspicious unused variable: unused variable that is bound with let or as, and
              doesn't start with an underscore (_) character.

              27   Innocuous unused variable: unused variable that is not bound with  let nor as,
              and doesn't start with an underscore (_) character.

              28    A  pattern  contains  a  constant  constructor  applied to the underscore (_)

              29   A non-escaped end-of-line was found in a  string  constant.   This  may  cause
              portability problems between Unix and Windows.

              30    Two  labels  or  constructors  of  the  same name are defined in two mutually
              recursive types.

              31   A module is linked twice in the same executable.

              32   Unused value declaration.

              33   Unused open statement.

              34   Unused type declaration.

              35   Unused for-loop index.

              36   Unused ancestor variable.

              37   Unused constructor.

              38   Unused extension constructor.

              39   Unused rec flag.

              40   Constructor or label name used out of scope.

              41   Ambiguous constructor or label name.

              42   Disambiguated constructor or label name.

              43   Nonoptional label applied as optional.

              44   Open statement shadows an already defined identifier.

              45   Open statement shadows an already defined label or constructor.

              46   Error in environment variable.

              47   Illegal attribute payload.

              48   Implicit elimination of optional arguments.

              49   Missing cmi file when looking up module alias.

              50   Unexpected documentation comment.

              59   Assignment on non-mutable value.

              60   Unused module declaration.

              61   Unannotated unboxable type in primitive declaration.

              62   Type constraint on GADT type declaration.

              63   Erroneous printed signature.

              64   -unsafe used with a preprocessor returning a syntax tree.

              65   Type declaration defining a new '()' constructor.

              66   Unused open! statement.

              67   Unused functor parameter.

              68   Pattern-matching depending on mutable state prevents the  remaining  arguments
              from being uncurried.

              The  letters  stand  for  the following sets of warnings.  Any letter not mentioned
              here corresponds to the empty set.

              A  all warnings

              C  1, 2

              D  3

              E  4

              F  5

              K  32, 33, 34, 35, 36, 37, 38, 39

              L  6

              M  7

              P  8

              R  9

              S  10

              U  11, 12

              V  13

              X  14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 30

              Y  26

              Z  27

              The default  setting  is  -w +a-4-7-9-27-29-30-32..42-44-45-48-50-60-66..70.   Note
              that  warnings 5 and 10 are not always triggered, depending on the internals of the
              type checker.

       -warn-error warning-list
              Mark as errors the warnings specified in the argument warning-list.   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: a + sign (or an uppercase letter)  marks
              the  corresponding  warnings  as fatal, a - sign (or a lowercase letter) turns them
              back into non-fatal warnings, and a @ sign both enables  and  marks  as  fatal  the
              corresponding warnings.

              Note:  it  is  not  recommended  to  use the -warn-error option in production code,
              because it will almost certainly prevent compiling your program with later versions
              of OCaml when they add new warnings or modify existing warnings.

              The default setting is -warn-error -a+31 (only warning 31 is fatal).

              Show the description of all available warning numbers.

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

              Include the runtime system in the generated program. This is the default.

              The  compiler  does  not  include the runtime system (nor a reference to it) in the
              generated program; it must be supplied separately.

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

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


       ocamlopt(1), ocamlrun(1), ocaml(1).
       The OCaml user's manual, chapter "Batch compilation".