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Erlang Run-Time System Application (ERTS)
Reference Manual
Version 5.10.4

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# erlc

### COMMAND

erlc

### COMMAND SUMMARY

Compiler

### DESCRIPTION

The erlc program provides a common way to run all compilers in the Erlang system. Depending on the extension of each input file, erlc will invoke the appropriate compiler. Regardless of which compiler is used, the same flags are used to provide parameters such as include paths and output directory.

The current working directory, ".", will not be included in the code path when running the compiler (to avoid loading Beam files from the current working directory that could potentially be in conflict with the compiler or Erlang/OTP system used by the compiler).

### EXPORTS

erlc flags file1.ext file2.ext...

Erlc compiles one or more files. The files must include the extension, for example .erl for Erlang source code, or .yrl for Yecc source code. Erlc uses the extension to invoke the correct compiler.

### Generally Useful Flags

The following flags are supported:

-I directory

  Instructs the compiler to search for include files in the specified directory. When encountering an -include or -include_lib directive, the compiler searches for header files in the following directories:

  - ".", the current working directory of the file server;

  - the base name of the compiled file;

  - the directories specified using the -I option. The directory specified last is searched first.

-o directory

  The directory where the compiler should place the output files. If not specified, output files will be placed in the current working directory.

-Dname

  Defines a macro.

-Dname=value

  Defines a macro with the given value. The value can be any Erlang term. Depending on the platform, the value may need to be quoted if the shell itself interprets certain characters. On Unix, terms which contain tuples and list must be quoted. Terms which contain spaces must be quoted on all platforms.

-Werror

  Makes all warnings into errors.

-Wnumber

  Sets warning level to number. Default is 1. Use -W0 to turn off warnings.

-W

  Same as -W1. Default.

-v

  Enables verbose output.

-b output-type

  Specifies the type of output file. Generally, output-type is the same as the file extension of the output file but without the period. This option will be ignored by compilers that have a a single output format.

-smp

  Compile using the SMP emulator. This is mainly useful for compiling native code, which needs to be compiled with the same run-time system that it should be run on.

-M

  Produces a Makefile rule to track headers dependencies. The rule is sent to stdout. No object file is produced.

-MF Makefile

  Like the -M option above, except that the Makefile is written to Makefile. No object file is produced.

-MD

  Same as -M -MF <File>.Pbeam.

-MT Target

  In conjunction with -M or -MF, change the name of the rule emitted to Target.

-MQ Target

  Like the -MT option above, except that characters special to make(1) are quoted.

-MP

  In conjunction with -M or -MF, add a phony target for each dependency.

-MG

  In conjunction with -M or -MF, consider missing headers as generated files and add them to the dependencies.

--

  Signals that no more options will follow. The rest of the arguments will be treated as file names, even if they start with hyphens.

+term

  A flag starting with a plus ('+') rather than a hyphen will be converted to an Erlang term and passed unchanged to the compiler. For instance, the export_all option for the Erlang compiler can be specified as follows:

      erlc +export_all file.erl

  Depending on the platform, the value may need to be quoted if the shell itself interprets certain characters. On Unix, terms which contain tuples and list must be quoted. Terms which contain spaces must be quoted on all platforms.

### Special Flags

The flags in this section are useful in special situations such as re-building the OTP system.

-pa directory

  Appends directory to the front of the code path in the invoked Erlang emulator. This can be used to invoke another compiler than the default one.

-pz directory

  Appends directory to the code path in the invoked Erlang emulator.

### Supported Compilers

.erl

  Erlang source code. It generates a .beam file.

  The options -P, -E, and -S are equivalent to +'P', +'E', and +'S', except that it is not necessary to include the single quotes to protect them from the shell.

  Supported options: -I, -o, -D, -v, -W, -b.

.yrl

  Yecc source code. It generates an .erl file.

  Use the -I option with the name of a file to use that file as a customized prologue file (the includefile option).

  Supported options: -o, -v, -I, -W (see above).

.mib

  MIB for SNMP. It generates a .bin file.

  Supported options: -I, -o, -W.

.bin

  A compiled MIB for SNMP. It generates a .hrl file.

  Supported options: -o, -v.

.rel

  Script file. It generates a boot file.

  Use the -I to name directories to be searched for application files (equivalent to the path in the option list for systools:make_script/2).

  Supported options: -o.

.asn1

  ASN1 file.

  Creates an .erl, .hrl, and .asn1db file from an .asn1 file. Also compiles the .erl using the Erlang compiler unless the +noobj options is given.

  Supported options: -I, -o, -b, -W.

.idl

  IC file.

  Runs the IDL compiler.

  Supported options: -I, -o.

### Environment Variables

ERLC_EMULATOR
  The command for starting the emulator. Default is erl in the same directory as the erlc program itself, or if it doesn't exist, erl in any of the directories given in the PATH environment variable.

### SEE ALSO

erl(1), compile(3), yecc(3), snmp(3)