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 Er‐
10 lang system. Depending on the extension of each input file, erlc in‐
11 vokes 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. De‐
45 faults 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 Er‐
52 lang 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 -WError:
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 op‐
73 tion is ignored by compilers that have a single output format.
74 -no-server:
76 Do not use the compile server.
77 -server:
79 Use the compile server.
80 -M:
82 Produces a Makefile rule to track header dependencies. The rule is
83 sent to stdout. No object file is produced.
84 -MMD:
86 Generate dependencies as a side-effect. The object file will be
87 produced as normal. This option overrides the option -M.
88 -MF <Makefile>:
90 As option -M, except that the Makefile is written to Makefile. No
91 object file is produced.
92 -MD:
94 Same as -M -MF <File>.Pbeam.
95 -MT <Target>:
97 In conjunction with option -M or -MF, changes the name of the rule
98 emitted to Target.
99 -MQ <Target>:
101 As option -MT, except that characters special to make/1 are quoted.
102 -MP:
104 In conjunction with option -M or -MF, adds a phony target for each
105 dependency.
106 -MG:
108 In conjunction with option -M or -MF, considers missing headers as
109 generated files and adds them to the dependencies.
110 --:
112 Signals that no more options will follow. The rest of the arguments
113 is treated as filenames, even if they start with hyphens.
114 +<Term>:
116 A flag starting with a plus (+) rather than a hyphen is converted
117 to an Erlang term and passed unchanged to the compiler. For exam‐
118 ple, option export_all for the Erlang compiler can be specified as
119 follows:
120 erlc +export_all file.erl
122 Depending on the platform, the value may need to be quoted if the
124 shell itself interprets certain characters. On Unix, terms contain‐
125 ing tuples and lists must be quoted. Terms containing spaces must
126 be quoted on all platforms.
127
129 The following flags are useful in special situations, such as rebuild‐
130 ing the OTP system:
131 -pa <Directory>:
133 Appends Directory to the front of the code path in the invoked Er‐
134 lang emulator. This can be used to invoke another compiler than the
135 default one.
136 -pz <Directory>:
138 Appends Directory to the code path in the invoked Erlang emulator.
139
141 The following compilers are supported:
142 .erl:
144 Erlang source code. It generates a .beam file.
145 Options -P, -E, and -S are equivalent to +'P', +'E', and +'S', ex‐
147 cept that it is not necessary to include the single quotes to pro‐
148 tect them from the shell.
149 Supported options: -I, -o, -D, -v, -W, -b.
151 .S:
153 Erlang assembler source code. It generates a .beam file.
154 Supported options: same as for .erl.
156 .core:
158 Erlang core source code. It generates a .beam file.
159 Supported options: same as for .erl.
161 .yrl:
163 Yecc source code. It generates an .erl file.
164 Use option -I with the name of a file to use that file as a custom‐
166 ized prologue file (option includefile).
167 Supported options: -o, -v, -I, -W.
169 .mib:
171 MIB for SNMP. It generates a .bin file.
172 Supported options: -I, -o, -W.
174 .bin:
176 A compiled MIB for SNMP. It generates a .hrl file.
177 Supported options: -o, -v.
179 .rel:
181 Script file. It generates a boot file.
182 Use option -I to name directories to be searched for application
184 files (equivalent to the path in the option list for sys‐
185 tools:make_script/2).
186 Supported option: -o.
188 .asn1:
190 ASN1 file. It creates an .erl, .hrl, and .asn1db file from an .asn1
191 file. Also compiles the .erl using the Erlang compiler unless op‐
192 tion +noobj is specified.
193 Supported options: -I, -o, -b, -W.
195 .idl:
197 IC file. It runs the IDL compiler.
198 Supported options: -I, -o.
200
202 The compile server can be used to potentially speed up the build of
203 multi-file projects by avoiding to start an Erlang system for each file
204 to compile. Whether it will speed up the build depends on the nature of
205 the project and the build machine.
206 By default, the compile server is not used. It can be enabled by giving
208 erlc the option -server or by setting the environment variable
209 ERLC_USE_SERVER to yes or true.
210 When the compile server is enabled, erlc will automatically use the
212 server if it is started and start the server if has not already
213 started. The server will terminate itself when it has been idle for
214 some number of seconds.
215 erlc and the compile server communicate using the Erlang distribution.
217 The compile server is started as a hidden node, with a name that in‐
218 cludes the current user. Thus, each user on a computer has their own
219 compile server.
220 Using the compile server does not always speed up the build, as the
222 compile server sometimes must be restarted to ensure correctness. Here
223 are some examples of situtations that force a restart:
224 * erlc wants to use a different version of Erlang than the compile
226 server is using.
227 * erlc wants to use different options for erl than the compile server
229 was started with. (A change to code path using the option -pa could
230 cause different parse transforms to be loaded. To be safe, the com‐
231 pile server will be restarted when any erl option is changed.)
232 * If the current working directory for erlc is different from the
234 working directory active when the compile server was started, and
235 if the compile server has active jobs, it will be restarted as soon
236 as those jobs have finished. (Build systems that build files ran‐
237 domly across multiple directories in parallel will probably not
238 benefit from the compile server.)
239
241 ERLC_EMULATOR:
242 The command for starting the emulator. Defaults to erl in the same
243 directory as the erlc program itself, or, if it does not exist, erl
244 in any of the directories specified in environment variable PATH.
245 ERLC_USE_SERVER:
247 Allowed values are yes or true to use the compile server, and no or
248 false to not use the compile server. If other values are given,
249 erlc will print a warning message and continue.
250 ERLC_SERVER_ID:
252 Tells erlc to identify the compile server by the given name, allow‐
253 ing a single user to run multiple unrelated builds in parallel
254 without them affecting each other, which can be useful for shared
255 build machines and the like. The name must be alphanumeric, and it
256 defaults to being empty.
257
259 erl(1), compile(3), yecc(3), snmp(3)
260Ericsson AB erts 12.3.2.1 erlc(1)