1OCAMLRUN(1) General Commands Manual OCAMLRUN(1)
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6 ocamlrun - The OCaml bytecode interpreter
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10 ocamlrun [ options ] filename argument ...
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14 The ocamlrun(1) command executes bytecode files produced by the linking
15 phase of the ocamlc(1) command.
16 The first non-option argument is taken to be the name of the file con‐
18 taining the executable bytecode. (That file is searched in the exe‐
19 cutable path as well as in the current directory.) The remaining argu‐
20 ments are passed to the OCaml program, in the string array Sys.argv.
21 Element 0 of this array is the name of the bytecode executable file;
22 elements 1 to n are the remaining arguments.
23 In most cases, the bytecode executable files produced by the ocamlc(1)
25 command are self-executable, and manage to launch the ocamlrun(1) com‐
26 mand on themselves automatically.
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30 The following command-line options are recognized by ocamlrun(1).
31 -b When the program aborts due to an uncaught exception, print a
33 detailed "back trace" of the execution, showing where the excep‐
34 tion was raised and which function calls were outstanding at
35 this point. The back trace is printed only if the bytecode exe‐
36 cutable contains debugging information, i.e. was compiled and
37 linked with the -g option to ocamlc(1) set. This option is
38 equivalent to setting the b flag in the OCAMLRUNPARAM environ‐
39 ment variable (see below).
40 -I dir Search the directory dir for dynamically-loaded libraries, in
42 addition to the standard search path.
43 -p Print the names of the primitives known to this version of
45 ocamlrun(1) and exit.
46 -v Direct the memory manager to print verbose messages on standard
48 error. This is equivalent to setting v=63 in the OCAMLRUNPARAM
49 environment variable (see below).
50 -version
52 Print version string and exit.
53 -vnum Print short version number and exit.
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58 The following environment variable are also consulted:
59 CAML_LD_LIBRARY_PATH
61 Additional directories to search for dynamically-loaded
62 libraries.
63 OCAMLLIB
65 The directory containing the OCaml standard library. (If OCAML‐
66 LIB is not set, CAMLLIB will be used instead.) Used to locate
67 the ld.conf configuration file for dynamic loading. If not set,
68 default to the library directory specified when compiling OCaml.
69 OCAMLRUNPARAM
71 Set the runtime system options and garbage collection parame‐
72 ters. (If OCAMLRUNPARAM is not set, CAMLRUNPARAM will be used
73 instead.) This variable must be a sequence of parameter speci‐
74 fications separated by commas. A parameter specification is a
75 letter, optionally followed by an = sign, a decimal number (or a
76 hexadecimal number prefixed by 0x), and an optional multiplier.
77 If the letter is followed by anything else, the corresponding
78 option is set to 1. Unknown letters are ignored. The options
79 are documented below; the last six correspond to the fields of
80 the control record documented in The OCaml user's manual, chap‐
81 ter "Standard Library", section "Gc".
82 b Trigger the printing of a stack backtrace when an uncaught
85 exception aborts the program. This option takes no argument.
86 p Turn on debugging support for ocamlyacc-generated parsers. When
88 this option is on, the pushdown automaton that executes the
89 parsers prints a trace of its actions. This option takes no
90 argument.
91 R Turn on randomization of all hash tables by default (see the
93 Hashtbl module of the standard library). This option takes no
94 argument.
95 h The initial size of the major heap (in words).
97 a (allocation_policy)
99 The policy used for allocating in the OCaml heap. Possible val‐
100 ues are 0 for the next-fit policy, and 1 for the first-fit pol‐
101 icy. Next-fit is usually faster, but first-fit is better for
102 avoiding fragmentation and the associated heap compactions.
103 s (minor_heap_size)
105 The size of the minor heap (in words).
106 i (major_heap_increment)
108 The default size increment for the major heap (in words).
109 o (space_overhead)
111 The major GC speed setting.
112 O (max_overhead)
114 The heap compaction trigger setting.
115 l (stack_limit)
117 The limit (in words) of the stack size.
118 M (custom_major_ratio)
120 Target ratio of floating garbage to major heap size for out-of-
121 heap memory held by custom values located in the major heap. The
122 GC speed is adjusted to try to use this much memory for dead
123 values that are not yet collected. Expressed as a percentage of
124 major heap size. The default value keeps the out-of-heap float‐
125 ing garbage about the same size as the in-heap overhead. Note:
126 this only applies to values allocated with caml_alloc_custom_mem
127 (e.g. bigarrays). Default: 44.
128 m (custom_minor_ratio)
130 Bound on floating garbage for out-of-heap memory held by custom
131 values in the minor heap. A minor GC is triggered when this much
132 memory is held by custom values located in the minor heap.
133 Expressed as a percentage of minor heap size. Note: this only
134 applies to values allocated with caml_alloc_custom_mem (e.g.
135 bigarrays).
136 Default: 100.
137 n (custom_minor_max_size)
139 Maximum amount of out-of-heap memory for each custom value allo‐
140 cated in the minor heap. When a custom value is allocated on the
141 minor heap and holds more than this many bytes, only this value
142 is counted against custom_minor_ratio and the rest is directly
143 counted against custom_major_ratio. Note: this only applies to
144 values allocated with caml_alloc_custom_mem (e.g. bigarrays).
145 Default: 8192 bytes.
146 v (verbose)
148 What GC messages to print to stderr. This is a sum of values
149 selected from the following:
150 0x001 Start of major GC cycle.
152 0x002 Minor collection and major GC slice.
154 0x004 Growing and shrinking of the heap.
156 0x008 Resizing of stacks and memory manager tables.
158 0x010 Heap compaction.
160 0x020 Change of GC parameters.
162 0x040 Computation of major GC slice size.
164 0x080 Calling of finalisation functions.
166 0x100 Startup messages (loading the bytecode executable file,
168 resolving shared libraries).
169 0x200 Computation of compaction-triggering condition.
171 0x400 Output GC statistics at program exit, in the same format
173 as Gc.print_stat.
174 The multiplier is k, M, or G, for multiplication by 2^10, 2^20,
176 and 2^30 respectively.
177 If the option letter is not recognized, the whole parameter is
179 ignored; if the equal sign or the number is missing, the value
180 is taken as 1; if the multiplier is not recognized, it is
181 ignored.
182 For example, on a 32-bit machine under bash, the command export
184 OCAMLRUNPARAM='s=256k,v=1' tells a subsequent ocamlrun to set
185 its initial minor heap size to 1 megabyte and to print a message
186 at the start of each major GC cycle.
187 CAMLRUNPARAM
189 If OCAMLRUNPARAM is not found in the environment, then CAMLRUN‐
190 PARAM will be used instead. If CAMLRUNPARAM is also not found,
191 then the default values will be used.
192 PATH List of directories searched to find the bytecode executable
194 file.
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198 ocamlc(1).
199 The OCaml user's manual, chapter "Runtime system".
200 OCAMLRUN(1)