scalac man page

scalac — Compiler for the Scala 2 language

Synopsis

scalac [ <options> ] <source files>

Parameters

<options>
Command line options. See Options below.
<source files>
One or more source files to be compiled (such as MyClass.scala).

Description

The scalac tool reads class and object definitions, written in the Scala programming language, and compiles them into bytecode class files.

By default, the compiler puts each class file in the same directory as its source file. You can specify a separate destination directory with -d (see Options, below).

Options

The compiler has a set of standard options that are supported on the current development environment and will be supported in future releases. An additional set of non-standard options are specific to the current virtual machine implementation and are subject to change in the future. Non-standard options begin with -X.

Standard Options

-Dproperty=value
Pass -Dproperty=value directly to the runtime system.
-J<flag>
Pass <flag> directly to the runtime system.
-P:<plugin:opt>
Pass an option to a plugin
-X
Print a synopsis of advanced options.
-bootclasspath <path>
Override location of bootstrap class files (where to find the standard built-in classes, such as "scala.List").
-classpath <path>

Specify where to find user class files (on Unix-based systems a colon-separated list of paths, on Windows-based systems, a semicolon-separate list of paths). This does not override the built-in ("boot") search path.

The default class path is the current directory. Setting the CLASSPATH variable or using the -classpath command-line option overrides that default, so if you want to include the current directory in the search path, you must include "." in the new settings.

-d <directory|jar>
Specify where to place generated class files.
-deprecation

Emit warning and location for usages of deprecated APIs.

Available since Scala version 2.2.1

-encoding <encoding>

Specify character encoding used by source files.

The default value is platform-specific (Linux: "UTF8", Windows: "Cp1252"). Executing the following code in the Scala interpreter will return the default value on your system:

scala> new java.io.InputStreamReader(System.in).getEncoding

-explaintypes
Explain type errors in more detail.
-extdirs <dirs>
Override location of installed extensions.
-g:{none,source,line,vars,notailcalls}

"none" generates no debugging info,

"source" generates only the source file attribute,

"line" generates source and line number information,

"vars" generates source, line number and local variable information,

"notailcalls" generates all of the above and will not perform tail call optimization.

-help
Print a synopsis of standard options.
-javabootclasspath <path>
Override Java boot classpath.
-javaextdirs <path>
Override Java extdirs classpath.
-no-specialization
Ignore @specialize annotations.
-nobootcp
Do not use the boot classpath for the Scala jar files.
-nowarn
Generate no warnings
-optimise
Generates faster bytecode by applying optimisations to the program.
-print
Print program with all Scala-specific features removed.
-sourcepath <path>
Specify location(s) of source files.
-target:<target>

Specify which backend to use (jvm-1.5,msil).

The default value is "jvm-1.5" (was "jvm-1.4" up to Scala version 2.6.1).

-toolcp <path>
Add to the runner classpath.
-unchecked

Enable detailed unchecked (erasure) warnings

Non variable type-arguments in type patterns are unchecked since they are eliminated by erasure

Available since Scala version 2.3.0

-uniqid
Uniquely tag all identifiers in debugging output.
-verbose
Output messages about what the compiler is doing
-version
Print product version and exit.
@<file>
A text file containing compiler arguments (options and source files)

Advanced Options

-Xassem-extdirs <dirs>
(Requires -target:msil) List of directories containing assemblies. default:lib.
-Xassem-name <file>
(Requires -target:msil) Name of the output assembly.
-Xassem-path <path>
(Requires -target:msil) List of assemblies referenced by the program.
-Xcheck-null
Warn upon selection of nullable reference
-Xcheckinit
Wrap field accessors to throw an exception on uninitialized access.
-Xdisable-assertions
Generate no assertions and assumptions
-Xelide-below <n>
Calls to @elidable methods are omitted if method priority is lower than argument.
-Xexperimental
Enable experimental extensions
-Xfatal-warnings
Fail the compilation if there are any warnings.
-Xfuture
Turn on future language features.
-Xgenerate-phase-graph <file>
Generate the phase graphs (outputs .dot files) to fileX.dot.
-Xlint
Enable recommended additional warnings.
-Xlog-implicits
Show more detail on why some implicits are not applicable.
-Xmax-classfile-name <n>
Maximum filename length for generated classes.
-Xmigration
Warn about constructs whose behavior may have changed between 2.7 and 2.8.
-Xno-forwarders
Do not generate static forwarders in mirror classes.
-Xno-uescape
Disable handling of \u unicode escapes
-Xnojline
Do not use JLine for editing.
-Xplugin:<file>
Load a plugin from a file
-Xplugin-disable:<plugin>
Disable a plugin
-Xplugin-list
Print a synopsis of loaded plugins
-Xplugin-require:<plugin>
Abort unless the given plugin(s) are available
-Xpluginsdir <path>
Path to search compiler plugins.
-Xprint:<phases>
Print out program after <phases> (see below).
-Xprint-icode
Log internal icode to *.icode files.
-Xprint-pos
Print tree positions, as offsets.
-Xprint-types
Print tree types (debugging option).
-Xprompt
Display a prompt after each error (debugging option).
-Xresident
Compiler stays resident, files to compile are read from standard input.
-Xscript <object>
Treat the source file as a script and wrap it in a main method.
-Xshow-class <class>
Show internal representation of class.
-Xshow-object <object>
Show internal representation of object.
-Xshow-phases
Print a synopsis of compiler phases.
-Xsource-reader <classname>
Specify a custom method for reading source files.
-Xsourcedir <path>
(Requires -target:msil) Mirror source folder structure in output directory..
-Xverify
Verify generic signatures in generated bytecode.
-Y
Print a synopsis of private options.

Compilation Phases

initial
initializing compiler
parse
parse source files
namer
create symbols
analyze
name and type analysis
refcheck
reference checking
uncurry
uncurry function types and applications
lambdalift
lambda lifter
typesasvalues
represent types as values
addaccessors
add accessors for constructor arguments
explicitouterclasses
make links from inner classes to enclosing one explicit
addconstructors
add explicit constructor for each class
tailcall
add tail-calls
wholeprog
perform whole program analysis
addinterfaces
add one interface per class
expandmixins
expand mixins by code copying
boxing
makes boxing explicit
erasure
type eraser
icode
generate icode
codegen
enable code generation
terminal
compilation terminated
all
matches all phases

Environment

JAVACMD
Specify the java command to be used for running the Scala code. Arguments may be specified as part of the environment variable; spaces, quotation marks, etc., will be passed directly to the shell for expansion.
JAVA_HOME
Specify JDK/JRE home directory. This directory is used to locate the java command unless JAVACMD variable set.
JAVA_OPTS

Specify the options to be passed to the java command defined by JAVACMD.

With Java 1.5 (or newer) one may for example configure the memory usage of the JVM as follows: JAVA_OPTS="-Xmx512M -Xms16M -Xss16M"

With GNU Java one may configure the memory usage of the GIJ as follows: JAVA_OPTS="--mx512m --ms16m"

Examples

Compile a Scala program to the current directory
scalac HelloWorld
Compile a Scala program to the destination directory classes
scalac -d classes HelloWorld.scala
Compile a Scala program using a user-defined java command
env JAVACMD=/usr/local/bin/cacao scalac -d classes HelloWorld.scala
Compile all Scala files found in the source directory src to the destination directory classes
scalac -d classes src/*.scala

Exit Status

scalac returns a zero exist status if it succeeds to compile the specified input files. Non zero is returned in case of failure.

Author

Written by Martin Odersky and other members of the Scala team.

Reporting Bugs

Report bugs to https://issues.scala-lang.org/.

See Also

fsc(1), scala(1), scaladoc(1), scalap(1)

Referenced By

fsc(1), scala(1), scaladoc(1), scalap(1).

March 2012 version 1.0 USER COMMANDS