OCAMLRUN(1) General Commands Manual OCAMLRUN(1)
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 con-
taining the executable bytecode. (That file is searched in the exe-
cutable path as well as in the current directory.) The remaining argu-
ments 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) com-
mand 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 excep-
tion was raised and which function calls were outstanding at
this point. The back trace is printed only if the bytecode exe-
cutable 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 environ-
ment variable (see below).
-I dir Search the directory dir for dynamically-loaded libraries, in
addition to the standard search path.
-p Print the names of the primitives known to this version of
ocamlrun(1) and exit.
-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 li-
braries.
OCAMLLIB
The directory containing the OCaml standard library. (If OCAML-
LIB 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 parame-
ters. (If OCAMLRUNPARAM is not set, CAMLRUNPARAM will be used
instead.) This variable must be a sequence of parameter speci-
fications 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 last six correspond to the fields of
the control record documented in The OCaml user's manual, chap-
ter "Standard Library", section "Gc".
b Trigger the printing of a stack backtrace when an uncaught ex-
ception aborts the program. This option takes no argument.
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 ar-
gument.
R Turn on randomization of all hash tables by default (see the
Hashtbl module of the standard library). This option takes no
argument.
h The initial size of the major heap (in words).
a (allocation_policy)
The policy used for allocating in the OCaml heap. Possible val-
ues 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.
s (minor_heap_size)
The size of the minor heap (in words).
i (major_heap_increment)
The default size increment for the major heap (in words).
o (space_overhead)
The major GC speed setting.
O (max_overhead)
The heap compaction trigger setting.
l (stack_limit)
The limit (in words) of the stack size.
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 float-
ing 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.
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. Ex-
pressed as a percentage of minor heap size. Note: this only ap-
plies to values allocated with caml_alloc_custom_mem (e.g. bi-
garrays).
Default: 100.
n (custom_minor_max_size)
Maximum amount of out-of-heap memory for each custom value allo-
cated 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.
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.
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 ig-
nored.
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 CAMLRUN-
PARAM 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)
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