# 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.

### 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_dir` directive, the compiler searches for header files in the following directories:
  1. `"."`, the current working directory of the file server;
  2. the base name of the compiled file;
  3. 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.
-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.
--
  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)

### AUTHORS

Björn Gustavsson - support@erlang.ericsson.se

erts 5.5.1
Copyright © 1991-2006 Ericsson AB