NAME

       ocaml - The OCaml interactive toplevel

SYNOPSIS

       ocaml [ options ] [ object-files ] [ script-file ]

DESCRIPTION

       The  ocaml(1)  command is the toplevel system for OCaml, that permits interactive use of the OCaml system
       through a read-eval-print loop. In this mode, the system repeatedly reads OCaml phrases from  the  input,
       then typechecks, compiles and evaluates them, then prints the inferred type and result value, if any. The
       system prints a # (sharp) prompt before reading each phrase.

       A  toplevel  phrase  can  span  several lines. It is terminated by ;; (a double-semicolon). The syntax of
       toplevel phrases is as follows.

       The toplevel system is started by the command ocaml(1).  Phrases are read on standard input, results  are
       printed on standard output, errors on standard error. End-of-file on standard input terminates ocaml(1).

       If  one or more object-files (ending in .cmo or .cma) are given, they are loaded silently before starting
       the toplevel.

       If a script-file is given, phrases are read silently from the file, errors  printed  on  standard  error.
       ocaml(1) exits after the execution of the last phrase.

OPTIONS

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

       -absname
              Show absolute filenames in error messages.

       -I directory
              Add  the  given  directory  to  the list of directories searched for source and compiled files. 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 path.

              Directories can also be added to the search path once the toplevel is running with the  #directory
              directive.

       -init file
              Load the given file instead of the default initialization file.  The default file is .ocamlinit in
              the current directory if it exists, otherwise .ocamlinit in the user's home directory.

       -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.

       -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.

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

       -noprompt
              Do not display any prompt when waiting for input.

       -nopromptcont
              Do not display the secondary prompt when waiting for  continuation  lines  in  multi-line  inputs.
              This should be used e.g. when running ocaml(1) in an emacs(1) window.

       -nostdlib
              Do  not  include the standard library directory in the list of directories searched for source and
              compiled files.

       -ppx command
              After parsing, pipe the abstract syntax tree through the preprocessor command.  The format of  the
              input and output of the preprocessor are not yet documented.

       -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.

       -rectypes
              Allow arbitrary recursive types during type-checking.  By default, only recursive types where  the
              recursion goes through an object type are supported.

       -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.

       -stdin Read the standard input as a script file rather than starting an interactive session.

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

       -unsafe
              Turn bound checking off on 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.

       -version
              Print version string and exit.

       -vnum  Print short version number and exit.

       -w warning-list
              Enable or disable warnings according to the argument warning-list.  See ocamlc(1) for  the  syntax
              of the warning-list argument.

       -warn-error warning-list
              Mark  as  fatal  the  warnings described by the argument warning-list.  Note that a warning is not
              triggered (and does not trigger an error) if it is disabled by the -w option.  See  ocamlc(1)  for
              the syntax of the warning-list argument.

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

       - file Use file as a script file name, even when it starts with a hyphen (-).

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

ENVIRONMENT VARIABLES

       LC_CTYPE
              If  set  to  iso_8859_1,  accented  characters  (from the ISO Latin-1 character set) in string and
              character literals are printed as is; otherwise, they are printed as decimal escape sequences.

       TERM   When printing error messages, the toplevel system attempts to underline visually the  location  of
              the error. It consults the TERM variable to determines the type of output terminal and look up its
              capabilities in the terminal database.

SEE ALSO

       ocamlc(1), ocamlopt(1), ocamlrun(1).
       The OCaml user's manual, chapter "The toplevel system".

                                                                                                        OCAML(1)