OCAMLC(1)

NAME
ocamlc - The OCaml bytecode compiler

SYNOPSIS
ocamlc [options] filename...
ocamlc.opt [options] filename...

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

    If the interface file x.mli exists, the implementation x.ml is checked against the corresponding compiled interface x.cmi, which must exist. If no interface x.mli is provided, the compilation of x.ml 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 x.ml.

•   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 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.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 below).

•   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.

Two versions of the bytecode compiler exist: ocamlc.byte is a bytecode executable (i.e. compiled with ocamlc(1) itself), while ocamlc.opt is a native executable (i.e. compiled with ocamlopt(1)). ocamlc.opt may not be available in all installations of OCaml. ocamlc is an alias for the fastest of the two, i.e. for ocamlc.opt if it is available, otherwise for ocamlc.byte.

OPTIONS
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.

-no-absname
    Do not try to show absolute filenames in error messages.

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

-bin-annot
    Dump detailed information about the compilation (types, bindings, tail-calls, etc) in binary format. The information for file src.ml 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 program.

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

    If -color is not provided, "OCAML_COLOR" is not set and the environment variable "NO_COLOR" is set, then color output is disabled. Otherwise, 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) holds.

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

    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.

-compat-32
    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.

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

-config-var
    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.

-custom
    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(1) would do.

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

-dllib-suffixed -llibname
    As for -dllib but the name recorded is mangled by ocamlrun(1) at program start-up time. This is used for C stub libraries; this option is used in particular by ocamlmklib -suffixed.

-dllpath dir
    Add 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 A.ml 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.

-no-g
    Do not record debugging information (default).

-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-variance
    Cause the compiler to print the computed variance of type parameters for every type declaration. Without this option, variance is printed only for private types or types without a manifest (e.g., abstract types).

-cmi-file filename
    Type-check the source implementation to be compiled against the specified interface file (bypasses the normal lookup for .mli and .cmi files).

-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 .ml.

-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).

-keep-docs
    Keep documentation strings in generated .cmi files.

-keep-locs
    Keep locations in generated .cmi files.

-keywords version+list
    Set keywords according to the version+list specification.

    This specification starts with an optional version number, defining the base set of keywords, followed by a + separated list of additional keywords to add to this base set. Without an explicit version number, the base set of keywords is the set of keywords in the current version of OCaml. Additional keywords that do not match any known keyword in the current version of the language trigger an error whenever they are present in the source code.

-labels
    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. Revert option -nolabels.

-launch-method method
    Specifies the mechanism used by normal bytecode executables to find the interpreter. The following methods are supported:

    exe A small executable stub launcher contained in the runtime-launch-info file is prepended to the bytecode image.

    sh  A #! header is used. If the full path to the required interpreter is not suitable for a #! line, a small shell script is generated instead, using the sh interpreter found in PATH.

    /path/interpreter
        As for sh, but if the interpreter cannot be used in #! line then /path/intepreter is used instead of searching for sh in PATH.

-linkall
    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.

-make-runtime
    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.

-match-context-rows number
    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.

-no-alias-deps
    Do not record dependencies for module aliases.

-no-app-funct
    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.

-noassert
    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.

-noautolink
    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.

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

-nostdlib
    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 -I.

-o filename
    Specify the name of the final output file, whether it is an executable, a compiled object (-c option), a library (-a option), a packed object (-pack option), or a C source or object file (-output-obj and -output-complete-obj options).

    The default output name for an executable depends on the platform, it is a.out on Unix, camlprog.exe on Windows.

    This can also be used when compiling but not linking an interface or implementation file (-c option), in which case it sets both the name of the cmi or cmo file, and of the compilation unit to the filename up to the first dot.

-opaque
    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.

-output-obj
    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).

-output-complete-obj
    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.

    The .cmo object files being combined must have been compiled with the appropriate -for-pack option. In the example above, a.cmo, b.cmo and c.cmo must have been compiled with ocamlc -for-pack P.

-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.

-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.

-principal
    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.

-no-principal
    Do not check principality of type inference. This is the default.

-rectypes
    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 dependencies.

-no-rectypes
    Do no allow arbitrary recursive types during type-checking. This is the default.

-runtime-search method
    Control whether the header used by normal bytecode executables is permitted to search for the interpreter, or requires it to be at a fixed location. The following methods are supported:

    disable
        A fixed absolute path to the interpreter is used, and the executable will not launch if the interpreter is not found at this location.

    fallback
        A fixed absolute path to the interpreter is used, but if the executable cannot find the interpreter at this location then it will search first in the directory containing the executable and then in PATH.

    enable
        The executable searches for the interpreter first in the directory containing the executable and then in PATH. No absolute path to the interpreter is recorded.

-runtime-variant suffix
    Add suffix to the name of the runtime library that will be used by the program. If OCaml was configured with them, the debug (d suffix) and instrument (i suffix) runtimes can be used.

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

-safer-matching
    Do not use type information to optimize pattern-matching. This allows to detect match failures even if a pattern-matching was wrongly assumed to be exhaustive. This only impacts GADT and polymorphic variant compilation.

-set-runtime-default setting=value
    When linking an executable, override the default value for a runtime setting. The only currently supported setting is:

    standard_library_default
        Specifies the default location used by the executable to locate the Standard Library. By default, this is the absolute path to the Standard Library the compiler itself was configured with.

-short-paths
    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.

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

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

-no-strict-sequence
    Left-hand part of a sequence need not have type unit. This is the default.

-unboxed-types
    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].

-no-unboxed-types
    When a type is unboxable it will be boxed unless annotated with [@@ocaml.unboxed]. This is the default.

-unsafe
    Turn bound checking off for array and string accesses (the v.(i) and s.[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.

-unsafe-string
    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 software.

-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.

-verbose
    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 warning-list.

    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 either a mnemonic warning specifier or a sequence of single character warning specifiers, with no separators between them. A mnemonic warning specifier is one of the following:

    +name
        Enable warning name.

    -name
        Disable warning name.

    @name
        Enable and mark as fatal warning name.

    A single character 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 (inclusive).

    +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 and mnemonic names are as follows:

    1 [comment-start]
        Suspicious-looking start-of-comment mark.

    2 [comment-not-end]
        Suspicious-looking end-of-comment mark.

    3   Deprecated feature.

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

    5 [ignored-partial-application]
        Partially applied function: expression whose result has function type and is ignored.

    6 [labels-omitted]
        Label omitted in function application.

    7 [method-override]
        Method overridden without using the "method!" keyword.

    8 [partial-match]
        Partial match: missing cases in pattern-matching.

    9 [missing-record-field-pattern]
        Missing fields in a record pattern.

    10 [non-unit-statement]
        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]
        Redundant case in a pattern matching (unused match case).

    12 [redundant-subpat]
        Redundant sub-pattern in a pattern-matching.

    13 [instance-variable-override]
        Override of an instance variable.

    14 [illegal-backslash]
        Illegal backslash escape in a string constant.

    15 [implicit-public-methods]
        Private method made public implicitly.

    16 [unerasable-optional-argument]
        Unerasable optional argument.

    17 [undeclared-virtual-method]
        Undeclared virtual method.

    18 [not-principal]
        Non-principal type.

    19 [non-principal-labels]
        Type without principality.

    20 [ignored-extra-argument]
        Unused function argument.

    21 [nonreturning-statement]
        Non-returning statement.

    22 [preprocessor]
        Preprocessor warning.

    23 [useless-record-with]
        Useless record with clause.

    24 [bad-module-name]
        Bad module name: the source file name is not a valid OCaml module name.

    25  Deprecated: now part of warning 8.

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

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

    28 [wildcard-arg-to-constant-constr]
        A pattern contains a constant constructor applied to the underscore (_) pattern.

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

    30 [duplicate-definitions]
        Two labels or constructors of the same name are defined in two mutually recursive types.

    31 [module-linked-twice]
        A module is linked twice in the same executable.

    32 [unused-value-declaration]
        Unused value declaration.

    33 [unused-open]
        Unused open statement.

    34 [unused-type-declaration]
        Unused type declaration.

    35 [unused-for-index]
        Unused for-loop index.

    36 [unused-ancestor]
        Unused ancestor variable.

    37 [unused-constructor]
        Unused constructor.

    38 [unused-extension]
        Unused extension constructor.

    39 [unused-rec-flag]
        Unused rec flag.

    40 [name-out-of-scope]
        Constructor or label name used out of scope.

    41 [ambiguous-name]
        Ambiguous constructor or label name.

    42 [disambiguated-name]
        Disambiguated constructor or label name.

    43 [nonoptional-label]
        Nonoptional label applied as optional.

    44 [open-shadow-identifier]
        Open statement shadows an already defined identifier.

    45 [open-shadow-label-constructor]
        Open statement shadows an already defined label or constructor.

    46 [bad-env-variable]
        Error in environment variable.

    47 [attribute-payload]
        Illegal attribute payload.

    48 [eliminated-optional-arguments]
        Implicit elimination of optional arguments.

    49 [no-cmi-file]
        Missing cmi file when looking up module alias.

    50 [unexpected-docstring]
        Unexpected documentation comment.

    51 [wrong-tailcall-expectation]
        Function call annotated with an incorrect @tailcall attribute

    52 [fragile-literal-pattern]
        Fragile constant pattern.

    53 [misplaced-attribute]
        Attribute cannot appear in this context.

    54 [duplicated-attribute]
        Attribute used more than once on an expression.

    55 [inlining-impossible]
        Inlining impossible.

    56 [unreachable-case]
        Unreachable case in a pattern-matching (based on type information).

    57 [ambiguous-var-in-pattern-guard]
        Ambiguous or-pattern variables under guard.

    58 [no-cmx-file]
        Missing cmx file.

    59 [flambda-assignment-to-non-mutable-value]
        Assignment on non-mutable value.

    60 [unused-module]
        Unused module declaration.

    61 [unboxable-type-in-prim-decl]
        Unannotated unboxable type in primitive declaration.

    62 [constraint-on-gadt]
        Type constraint on GADT type declaration.

    63 [erroneous-printed-signature]
        Erroneous printed signature.

    64 [unsafe-array-syntax-without-parsing]
        -unsafe used with a preprocessor returning a syntax tree.

    65 [redefining-unit]
        Type declaration defining a new '()' constructor.

    66 [unused-open-bang]
        Unused open! statement.

    67 [unused-functor-parameter]
        Unused functor parameter.

    68 [match-on-mutable-state-prevent-uncurry]
        Pattern-matching depending on mutable state prevents the remaining arguments from being uncurried.

    69 [unused-field]
        Unused record field.

    70 [missing-mli]
        Missing interface file.

    71 [unused-tmc-attribute]
        Unused @tail_mod_cons attribute

    72 [tmc-breaks-tailcall]
        A tail call is turned into a non-tail call by the @tail_mod_cons transformation.

    73 [generative-application-expects-unit]
        A generative functor is applied to an empty structure (struct end) rather than to ().

    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..70-74. 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 (no warning is fatal).

-warn-help
    Show the description of all available warning numbers.

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

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

-without-runtime
    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.

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