brief:

Restricts error and warning messages to a single line of output. As of OTP 24, the compiler will by default also display the part of the source code that the message refers to.

basic_validation:

This option is a fast way to test whether a module will compile successfully. This is useful for code generators that want to verify the code that they emit. No code is generated. If warnings are enabled, warnings generated by the erl_lint module (such as warnings for unused variables and functions) are also returned.

strong_validation:

Similar to option basic_validation. No code is generated, but more compiler passes are run to ensure that warnings generated by the optimization passes are generated (such as clauses that will not match, or expressions that are guaranteed to fail with an exception at runtime).

binary:

The compiler returns the object code in a binary instead of creating an object file. If successful, the compiler returns {ok,ModuleName,Binary}.

bin_opt_info:

The compiler will emit informational warnings about binary matching optimizations (both successful and unsuccessful). For more information, see the section about bin_opt_info in the Efficiency Guide.

{compile_info, [{atom(), term()}]}:

Allows compilers built on top of compile to attach extra compilation metadata to the compile_info chunk in the generated beam file.

compressed:

The compiler will compress the generated object code, which can be useful for embedded systems.

debug_info:

{debug_info, {Backend, Data}}:

{debug_info_key,KeyString}:

{debug_info_key,{Mode,KeyString}}:

encrypt_debug_info:

deterministic:

Omit the options and source tuples in the list returned by Module:module_info(compile), and reduce the paths in stack traces to the module name alone. This option will make it easier to achieve reproducible builds.

{feature, Feature, enable | disable}:

Enable (disable) the feature Feature during compilation. The special feature all can be used to enable (disable) all features.

A feature can also be enabled (disabled) using the -feature(Feature, enable | disable). module directive. Note that this directive can only be present in a prefix of the file, before exports and function definitions. This is the preferred method of enabling and disabling features, since it is a local property of a module.

makedep:

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

-module(module).
-include_lib("eunit/include/eunit.hrl").
-include("header.hrl").

module.beam: module.erl \


  /usr/local/lib/erlang/lib/eunit/include/eunit.hrl \


  header.hrl

makedep_side_effect:

The dependencies are created as a side effect to the normal compilation process. This means that the object file will also be produced. This option override the makedep option.

{makedep_output, Output}:

Writes generated rules to Output instead of the default <File>.Pbeam. Output can be a filename or an io_device(). To write to stdout, use standard_io. However, if binary is set, nothing is written to Output and the result is returned to the caller with {ok, ModuleName, Binary}.

{makedep_target, Target}:

Changes the name of the rule emitted to Target.

makedep_quote_target:

Characters in Target special to make(1) are quoted.

makedep_add_missing:

Considers missing headers as generated files and adds them to the dependencies.

makedep_phony:

Adds a phony target for each dependency.

'P':

Produces a listing of the parsed code, after preprocessing and parse transforms, in the file <File>.P. No object file is produced.

'E':

Produces a listing of the code, after all source code transformations have been performed, in the file <File>.E. No object file is produced.

'S':

Produces a listing of the assembler code in the file <File>.S. No object file is produced.

recv_opt_info:

The compiler will emit informational warnings about selective receive optimizations (both successful and unsuccessful). For more information, see the section about selective receive optimization in the Efficiency Guide.

report_errors/report_warnings:

Causes errors/warnings to be printed as they occur.

report:

A short form for both report_errors and report_warnings.

return_errors:

If this flag is set, {error,ErrorList,WarningList} is returned when there are errors.

return_warnings:

If this flag is set, an extra field, containing WarningList, is added to the tuples returned on success.

warnings_as_errors:

Causes warnings to be treated as errors. This option is supported since R13B04.

{error_location,line | column}:

If the value of this flag is line, the location ErrorLocation of warnings and errors is a line number. If the value is column, ErrorLocation includes both a line number and a column number. Default is column. This option is supported since Erlang/OTP 24.0.

return:

A short form for both return_errors and return_warnings.

verbose:

Causes more verbose information from the compiler, describing what it is doing.

{source,FileName}:

Overrides the source file name as presented in module_info(compile) and stack traces.

absolute_source:

Turns the source file name (as presented in module_info(compile) and stack traces) into an absolute path, which helps external tools like perf and gdb find Erlang source code.

{outdir,Dir}:

Sets a new directory for the object code. The current directory is used for output, except when a directory has been specified with this option.

export_all:

Causes all functions in the module to be exported.

{i,Dir}:

Adds Dir to the list of directories to be searched when including a file. When encountering an -include or -include_lib directive, the compiler searches for header files in the following directories:

{d,Macro}:

{d,Macro,Value}:

Defines a macro Macro to have the value Value. Macro is of type atom, and Value can be any term. The default Value is true.

{parse_transform,Module}:

Causes the parse transformation function Module:parse_transform/2 to be applied to the parsed code before the code is checked for errors.

from_abstr:

The input file is expected to contain Erlang terms representing forms in abstract format (default file suffix ".abstr"). Note that the format of such terms can change between releases.

from_asm:

The input file is expected to be assembler code (default file suffix ".S"). Notice that the format of assembler files is not documented, and can change between releases.

from_core:

The input file is expected to be core code (default file suffix ".core"). Notice that the format of core files is not documented, and can change between releases.

no_spawn_compiler_process:

By default, all code is compiled in a separate process which is terminated at the end of compilation. However, some tools, like Dialyzer or compilers for other BEAM languages, may already manage their own worker processes and spawning an extra process may slow the compilation down. In such scenarios, you can pass this option to stop the compiler from spawning an additional process.

no_strict_record_tests:

This option is not recommended.

no_error_module_mismatch:

Normally the compiler verifies that the module name given in the source code is the same as the base name of the output file and refuses to generate an output file if there is a mismatch. If you have a good reason (or other reason) for having a module name unrelated to the name of the output file, this option disables that verification (there will not even be a warning if there is a mismatch).

{no_auto_import,[{F,A}, ...]}:

Makes the function F/A no longer being auto-imported from the erlang module, which resolves BIF name clashes. This option must be used to resolve name clashes with BIFs auto-imported before R14A, if it is needed to call the local function with the same name as an auto-imported BIF without module prefix.

-compile({no_auto_import,[error/1]}).

no_auto_import:

Do not auto-import any functions from erlang module.

no_line_info:

Omits line number information to produce a slightly smaller output file.

no_lint:

Skips the pass that checks for errors and warnings. Only applicable together with the from_abstr option. This is mainly for implementations of other languages on top of Erlang, which have already done their own checks to guarantee correctness of the code.

{extra_chunks, [{binary(), binary()}]}:

Pass extra chunks to be stored in the .beam file. The extra chunks must be a list of tuples with a four byte binary as chunk name followed by a binary with the chunk contents. See beam_lib for more information.

{check_ssa, Tag :: atom()}:

Parse and check assertions on the structure and content of the BEAM SSA code produced by the compiler. The Tag indicates the set of assertions to check and after which compiler pass the check is performed. This option is internal to the compiler and can be changed or removed at any time without prior warning.

*

A warn_xxx form, to turn on the warning.

*

A nowarn_xxx form, to turn off the warning.

{warn_format, Verbosity}:

Causes warnings to be emitted for malformed format strings as arguments to io:format and similar functions.

nowarn_bif_clash:

This option is removed, it generates a fatal error if used.

The use of this option has always been discouraged. As from R14A, it is an error to use it.

To resolve BIF clashes, use explicit module names or the {no_auto_import,[F/A]} compiler directive.

{nowarn_bif_clash, FAs}:

This option is removed, it generates a fatal error if used.

To resolve BIF clashes, use explicit module names or the {no_auto_import,[F/A]} compiler directive.

nowarn_export_all:

Turns off warnings for uses of the export_all option. Default is to emit a warning if option export_all is also given.

warn_export_vars:

Emits warnings for all implicitly exported variables referred to after the primitives where they were first defined. By default, the compiler only emits warnings for exported variables referred to in a pattern.

nowarn_shadow_vars:

Turns off warnings for "fresh" variables in functional objects or list comprehensions with the same name as some already defined variable. Default is to emit warnings for such variables.

warn_keywords:

Emits warnings when the code contains atoms that are used as keywords in some feature. When the feature is enabled, any occurrences will lead to a syntax error. To prevent this, the atom has to be renamed or quoted.

nowarn_unused_function:

Turns off warnings for unused local functions. Default is to emit warnings for all local functions that are not called directly or indirectly by an exported function. The compiler does not include unused local functions in the generated beam file, but the warning is still useful to keep the source code cleaner.

{nowarn_unused_function, FAs}:

Turns off warnings for unused local functions like nowarn_unused_function does, but only for the mentioned local functions. FAs is a tuple {Name,Arity} or a list of such tuples.

nowarn_deprecated_function:

Turns off warnings for calls to deprecated functions. Default is to emit warnings for every call to a function known by the compiler to be deprecated. Notice that the compiler does not know about attribute -deprecated(), but uses an assembled list of deprecated functions in Erlang/OTP. To do a more general check, the Xref tool can be used. See also xref(3) and the function xref:m/1, also accessible through the function c:xm/1.

{nowarn_deprecated_function, MFAs}:

Turns off warnings for calls to deprecated functions like nowarn_deprecated_function does, but only for the mentioned functions. MFAs is a tuple {Module,Name,Arity} or a list of such tuples.

nowarn_deprecated_type:

Turns off warnings for use of deprecated types. Default is to emit warnings for every use of a type known by the compiler to be deprecated.

nowarn_removed:

Turns off warnings for calls to functions that have been removed. Default is to emit warnings for every call to a function known by the compiler to have been recently removed from Erlang/OTP.

{nowarn_removed, ModulesOrMFAs}:

Turns off warnings for calls to modules or functions that have been removed. Default is to emit warnings for every call to a function known by the compiler to have been recently removed from Erlang/OTP.

nowarn_obsolete_guard:

Turns off warnings for calls to old type testing BIFs, such as pid/1 and list/1. See the Erlang Reference Manual for a complete list of type testing BIFs and their old equivalents. Default is to emit warnings for calls to old type testing BIFs.

warn_unused_import:

Emits warnings for unused imported functions. Default is to emit no warnings for unused imported functions.

nowarn_underscore_match:

By default, warnings are emitted when a variable that begins with an underscore is matched after being bound. Use this option to turn off this kind of warning.

nowarn_unused_vars:

By default, warnings are emitted for unused variables, except for variables beginning with an underscore ("Prolog style warnings"). Use this option to turn off this kind of warning.

nowarn_unused_record:

Turns off warnings for unused record definitions. Default is to emit warnings for unused locally defined records.

{nowarn_unused_record, RecordNames}:

Turns off warnings for unused record definitions. Default is to emit warnings for unused locally defined records.

nowarn_unused_type:

Turns off warnings for unused type declarations. Default is to emit warnings for unused local type declarations.

nowarn_nif_inline:

By default, warnings are emitted when inlining is enabled in a module that may load NIFs, as the compiler may inline NIF fallbacks by accident. Use this option to turn off this kind of warnings.

warn_missing_spec:

By default, warnings are not emitted when a specification (or contract) for an exported function is not given. Use this option to turn on this kind of warning.

warn_missing_spec_all:

By default, warnings are not emitted when a specification (or contract) for an exported or unexported function is not given. Use this option to turn on this kind of warning.

nowarn_redefined_builtin_type:

By default, a warning is emitted when a built-in type is locally redefined. Use this option to turn off this kind of warning.

{nowarn_redefined_builtin_type, Types}:

By default, a warning is emitted when a built-in type is locally redefined. Use this option to turn off this kind of warning for the types in Types, where Types is a tuple {TypeName,Arity} or a list of such tuples.

nowarn_opportunistic:

Disable all opportunistic warnings.

nowarn_failed:

Disable warnings for expressions that will always fail (such as atom+42).

nowarn_ignored:

Disable warnings for expressions whose values are ignored.

nowarn_nomatch:

Disable warnings for patterns that will never match (such as a=b) and for guards that always evaluate to false.