Provided by: ocaml-base_4.14.1-1ubuntu1_amd64 
NAME
ocamlrun - The OCaml bytecode interpreter
SYNOPSIS
ocamlrun [ options ] filename argument ...
DESCRIPTION
The ocamlrun(1) command executes bytecode files produced by the linking phase of the
ocamlc(1) command.
The first non-option argument is taken to be the name of the file containing the
executable bytecode. (That file is searched in the executable path as well as in the
current directory.) The remaining arguments are passed to the OCaml program, in the string
array Sys.argv. Element 0 of this array is the name of the bytecode executable file;
elements 1 to n are the remaining arguments.
In most cases, the bytecode executable files produced by the ocamlc(1) command are self-
executable, and manage to launch the ocamlrun(1) command on themselves automatically.
OPTIONS
The following command-line options are recognized by ocamlrun(1).
-b When the program aborts due to an uncaught exception, print a detailed "back trace"
of the execution, showing where the exception was raised and which function calls
were outstanding at this point. The back trace is printed only if the bytecode
executable contains debugging information, i.e. was compiled and linked with the -g
option to ocamlc(1) set. This option is equivalent to setting the b flag in the
OCAMLRUNPARAM environment variable (see below).
-I dir Search the directory dir for dynamically-loaded libraries, in addition to the
standard search path.
-m file
Print the magic number of the bytecode executable file and exit.
-M Print the magic number expected for bytecode executables by this version of the
runtime and exit.
-p Print the names of the primitives known to this version of ocamlrun(1) and exit.
-t Increment the trace level for the debug runtime (ignored by the standard runtime).
-v Direct the memory manager to print verbose messages on standard error. This is
equivalent to setting v=63 in the OCAMLRUNPARAM environment variable (see below).
-version
Print version string and exit.
-vnum Print short version number and exit.
ENVIRONMENT VARIABLES
The following environment variable are also consulted:
CAML_LD_LIBRARY_PATH
Additional directories to search for dynamically-loaded libraries.
OCAMLLIB
The directory containing the OCaml standard library. (If OCAMLLIB is not set,
CAMLLIB will be used instead.) Used to locate the ld.conf configuration file for
dynamic loading. If not set, default to the library directory specified when
compiling OCaml.
OCAMLRUNPARAM
Set the runtime system options and garbage collection parameters. (If
OCAMLRUNPARAM is not set, CAMLRUNPARAM will be used instead.) This variable must
be a sequence of parameter specifications separated by commas. A parameter
specification is a letter, optionally followed by an = sign, a decimal number (or a
hexadecimal number prefixed by 0x), and an optional multiplier. If the letter is
followed by anything else, the corresponding option is set to 1. Unknown letters
are ignored. The options are documented below; the options a, i, l, m, M, n, o, O,
s, v, w correspond to the fields of the control record documented in The OCaml
user's manual, chapter "Standard Library", section "Gc".
a (allocation_policy)
The policy used for allocating in the OCaml heap. Possible values are 0 for
the next-fit policy, 1 for the first-fit policy, and 2 for the best-fit
policy. The default is 2. See the Gc module documentation for details.
b Trigger the printing of a stack backtrace when an uncaught exception aborts
the program. This option takes no argument.
c (cleanup_on_exit) Shut the runtime down gracefully on exit. The option also
enables pooling (as in caml_startup_pooled). This mode can be used to detect
leaks with a third-party memory debugger.
h The initial size of the major heap (in words).
H Allocate heap chunks by mmapping huge pages. Huge pages are locked into
memory, and are not swapped.
i (major_heap_increment)
The default size increment for the major heap (in words if greater than
1000, else in percents of the heap size).
l (stack_limit)
The limit (in words) of the stack size.
m (custom_minor_ratio)
Bound on floating garbage for out-of-heap memory held by custom values in
the minor heap. A minor GC is triggered when this much memory is held by
custom values located in the minor heap. Expressed as a percentage of minor
heap size. Note: this only applies to values allocated with
caml_alloc_custom_mem (e.g. bigarrays).
Default: 100.
M (custom_major_ratio)
Target ratio of floating garbage to major heap size for out-of-heap memory
held by custom values located in the major heap. The GC speed is adjusted to
try to use this much memory for dead values that are not yet collected.
Expressed as a percentage of major heap size. The default value keeps the
out-of-heap floating garbage about the same size as the in-heap overhead.
Note: this only applies to values allocated with caml_alloc_custom_mem (e.g.
bigarrays). Default: 44.
n (custom_minor_max_size)
Maximum amount of out-of-heap memory for each custom value allocated in the
minor heap. When a custom value is allocated on the minor heap and holds
more than this many bytes, only this value is counted against
custom_minor_ratio and the rest is directly counted against
custom_major_ratio. Note: this only applies to values allocated with
caml_alloc_custom_mem (e.g. bigarrays). Default: 8192 bytes.
o (space_overhead)
The major GC speed setting.
O (max_overhead)
The heap compaction trigger setting.
p Turn on debugging support for ocamlyacc-generated parsers. When this option
is on, the pushdown automaton that executes the parsers prints a trace of
its actions. This option takes no argument.
R Turn on randomization of all hash tables by default (see the Hashtbl module
of the standard library). This option takes no argument.
s (minor_heap_size)
The size of the minor heap (in words).
t Set the trace level for the debug runtime (ignored by the standard runtime).
v (verbose)
What GC messages to print to stderr. This is a sum of values selected from
the following:
0x001 Start and end of major GC cycle.
0x002 Minor collection and major GC slice.
0x004 Growing and shrinking of the heap.
0x008 Resizing of stacks and memory manager tables.
0x010 Heap compaction.
0x020 Change of GC parameters.
0x040 Computation of major GC slice size.
0x080 Calling of finalisation functions.
0x100 Startup messages (loading the bytecode executable file, resolving
shared libraries).
0x200 Computation of compaction-triggering condition.
0x400 Output GC statistics at program exit, in the same format as
Gc.print_stat.
w (window_size)
Set size of the window used by major GC for smoothing out variations in its
workload. This is an integer between 1 and 50. (Default: 1)
W Print runtime warnings to stderr (such as Channel opened on file dies
without being closed, unflushed data, etc.)
The multiplier is k, M, or G, for multiplication by 2^10, 2^20, and 2^30
respectively.
If the option letter is not recognized, the whole parameter is ignored; if the
equal sign or the number is missing, the value is taken as 1; if the multiplier is
not recognized, it is ignored.
For example, on a 32-bit machine under bash, the command export
OCAMLRUNPARAM='s=256k,v=1' tells a subsequent ocamlrun to set its initial minor
heap size to 1 megabyte and to print a message at the start of each major GC cycle.
CAMLRUNPARAM
If OCAMLRUNPARAM is not found in the environment, then CAMLRUNPARAM will be
used instead. If CAMLRUNPARAM is also not found, then the default values
will be used.
PATH List of directories searched to find the bytecode executable file.
SEE ALSO
ocamlc(1).
The OCaml user's manual, chapter "Runtime system".
OCAMLRUN(1)