1erlc(1) User Commands erlc(1)
2
6 erlc - Compiler
7
9 The erlc program provides a common way to run all compilers in the
10 Erlang system. Depending on the extension of each input file, erlc
11 invokes the appropriate compiler. Regardless of which compiler is used,
12 the same flags are used to provide parameters, such as include paths
13 and output directory.
14 The current working directory, ".", is not included in the code path
16 when running the compiler. This is to avoid loading Beam files from the
17 current working directory that could potentially be in conflict with
18 the compiler or the Erlang/OTP system used by the compiler.
19
21 erlc flags file1.ext file2.ext...
22 Compiles one or more files. The files must include the exten‐
24 sion, for example, .erl for Erlang source code, or .yrl for Yecc
25 source code. Erlc uses the extension to invoke the correct com‐
26 piler.
27
29 The following flags are supported:
30 -I <Directory>:
32 Instructs the compiler to search for include files in the Direc‐
33 tory. When encountering an -include or -include_lib directive, the
34 compiler searches for header files in the following directories:
35 * ".", the current working directory of the file server
37 * The base name of the compiled file
39 * The directories specified using option -I; the directory speci‐
41 fied last is searched first
42 -o <Directory>:
44 The directory where the compiler is to place the output files.
45 Defaults to the current working directory.
46 -D<Name>:
48 Defines a macro.
49 -D<Name>=<Value>:
51 Defines a macro with the specified value. The value can be any
52 Erlang term. Depending on the platform, the value may need to be
53 quoted if the shell itself interprets certain characters. On Unix,
54 terms containing tuples and lists must be quoted. Terms containing
55 spaces must be quoted on all platforms.
56 -W<Error>:
58 Makes all warnings into errors.
59 -W<Number>:
61 Sets warning level to Number. Defaults to 1. To turn off warnings,
62 use -W0.
63 -W:
65 Same as -W1. Default.
66 -v:
68 Enables verbose output.
69 -b <Output_type>:
71 Specifies the type of output file. Output_type is the same as the
72 file extension of the output file, but without the period. This
73 option is ignored by compilers that have a single output format.
74 -smp:
76 Compiles using the SMP emulator. This is mainly useful for compil‐
77 ing native code, which must be compiled with the same runtime sys‐
78 tem that it is to be run on.
79 -no-server:
81 Do not use the compile server.
82 -server:
84 Use the compile server.
85 -M:
87 Produces a Makefile rule to track header dependencies. The rule is
88 sent to stdout. No object file is produced.
89 -MMD:
91 Generate dependencies as a side-effect. The object file will be
92 produced as normal. This option overrides the option -M.
93 -MF <Makefile>:
95 As option -M, except that the Makefile is written to Makefile. No
96 object file is produced.
97 -MD:
99 Same as -M -MF <File>.Pbeam.
100 -MT <Target>:
102 In conjunction with option -M or -MF, changes the name of the rule
103 emitted to Target.
104 -MQ <Target>:
106 As option -MT, except that characters special to make/1 are quoted.
107 -MP:
109 In conjunction with option -M or -MF, adds a phony target for each
110 dependency.
111 -MG:
113 In conjunction with option -M or -MF, considers missing headers as
114 generated files and adds them to the dependencies.
115 --:
117 Signals that no more options will follow. The rest of the arguments
118 is treated as filenames, even if they start with hyphens.
119 +<Term>:
121 A flag starting with a plus (+) rather than a hyphen is converted
122 to an Erlang term and passed unchanged to the compiler. For exam‐
123 ple, option export_all for the Erlang compiler can be specified as
124 follows:
125 erlc +export_all file.erl
127 Depending on the platform, the value may need to be quoted if the
129 shell itself interprets certain characters. On Unix, terms contain‐
130 ing tuples and lists must be quoted. Terms containing spaces must
131 be quoted on all platforms.
132
134 The following flags are useful in special situations, such as rebuild‐
135 ing the OTP system:
136 -pa <Directory>:
138 Appends Directory to the front of the code path in the invoked
139 Erlang emulator. This can be used to invoke another compiler than
140 the default one.
141 -pz <Directory>:
143 Appends Directory to the code path in the invoked Erlang emulator.
144
146 The following compilers are supported:
147 .erl:
149 Erlang source code. It generates a .beam file.
150 Options -P, -E, and -S are equivalent to +'P', +'E', and +'S',
152 except that it is not necessary to include the single quotes to
153 protect them from the shell.
154 Supported options: -I, -o, -D, -v, -W, -b.
156 .S:
158 Erlang assembler source code. It generates a .beam file.
159 Supported options: same as for .erl.
161 .core:
163 Erlang core source code. It generates a .beam file.
164 Supported options: same as for .erl.
166 .yrl:
168 Yecc source code. It generates an .erl file.
169 Use option -I with the name of a file to use that file as a custom‐
171 ized prologue file (option includefile).
172 Supported options: -o, -v, -I, -W.
174 .mib:
176 MIB for SNMP. It generates a .bin file.
177 Supported options: -I, -o, -W.
179 .bin:
181 A compiled MIB for SNMP. It generates a .hrl file.
182 Supported options: -o, -v.
184 .rel:
186 Script file. It generates a boot file.
187 Use option -I to name directories to be searched for application
189 files (equivalent to the path in the option list for sys‐
190 tools:make_script/2).
191 Supported option: -o.
193 .asn1:
195 ASN1 file. It creates an .erl, .hrl, and .asn1db file from an .asn1
196 file. Also compiles the .erl using the Erlang compiler unless
197 option +noobj is specified.
198 Supported options: -I, -o, -b, -W.
200 .idl:
202 IC file. It runs the IDL compiler.
203 Supported options: -I, -o.
205
207 The compile server can be used to potentially speed up the build of
208 multi-file projects by avoiding to start an Erlang system for each file
209 to compile. Whether it will speed up the build depends on the nature of
210 the project and the build machine.
211 By default, the compile server is not used. It can be enabled by giving
213 erlc the option -server or by setting the environment variable
214 ERLC_USE_SERVER to yes or true.
215 When the compile server is enabled, erlc will automatically use the
217 server if it is started and start the server if has not already
218 started. The server will terminate itself when it has been idle for
219 some number of seconds.
220 erlc and the compile server communicate using the Erlang distribution.
222 The compile server is started as a hidden node, with a name that
223 includes the current user. Thus, each user on a computer has their own
224 compile server.
225 Using the compile server does not always speed up the build, as the
227 compile server sometimes must be restarted to ensure correctness. Here
228 are some examples of situtations that force a restart:
229 * erlc wants to use a different version of Erlang than the compile
231 server is using.
232 * erlc wants to use different options for erl than the compile server
234 was started with. (A change to code path using the option -pa could
235 cause different parse transforms to be loaded. To be safe, the com‐
236 pile server will be restarted when any erl option is changed.)
237 * If the current working directory for erlc is different from the
239 working directory active when the compile server was started, and
240 if the compile server has active jobs, it will be restarted as soon
241 as those jobs have finished. (Build systems that build files ran‐
242 domly across multiple directories in parallel will probably not
243 benefit from the compile server.)
244
246 ERLC_EMULATOR:
247 The command for starting the emulator. Defaults to erl in the same
248 directory as the erlc program itself, or, if it does not exist, erl
249 in any of the directories specified in environment variable PATH.
250 ERLC_USE_SERVER:
252 Allowed values are yes or true to use the compile server, and no or
253 false to not use the compile server. If other values are given,
254 erlc will print a warning message and continue.
255 ERLC_SERVER_ID:
257 Tells erlc to identify the compile server by the given name, allow‐
258 ing a single user to run multiple unrelated builds in parallel
259 without them affecting each other, which can be useful for shared
260 build machines and the like. The name must be alphanumeric, and it
261 defaults to being empty.
262
264 erl(1), compile(3), yecc(3), snmp(3)
265Ericsson AB erts 10.7.1 erlc(1)