Compilation Options

erl_opts

Purpose: Erlang compiler options

Type: [term()]

Common Options:

{erl_opts, [
    debug_info,                     % Include debug information
    warnings_as_errors,             % Treat warnings as errors
    warn_export_vars,               % Warn about exported variables
    warn_unused_import,             % Warn about unused imports
    warn_missing_spec,              % Warn about missing specs
    {parse_transform, Module},      % Apply parse transform
    {d, 'MACRO'},                   % Define macro
    {d, 'MACRO', Value},            % Define macro with value
    {i, "include"},                 % Include directory
    {i, "/abs/path/include"},       % Absolute include path
    no_debug_info,                  % Exclude debug information
    inline_list_funcs,              % Inline list functions
    {platform_define, Regex, Def},  % Platform-specific defines
    {src_dirs, ["src", "lib"]},     % Source directories
    compressed,                     % Compress beam files
    warn_export_all,                % Warn on export_all
    warn_shadow_vars,               % Warn about shadowed variables
    warn_obsolete_guard,            % Warn about obsolete guards
    warn_unused_record,             % Warn about unused records
    warn_unused_vars,               % Warn about unused variables
    nowarn_deprecated_function,     % Don't warn on deprecated functions
    {nowarn_unused_function, [{F,A}]}, % Specific functions
    {nowarn_unused_type, [{T,A}]}   % Specific types
]}.

Warning Control:

{erl_opts, [
    {warn_format, 2},               % Warning level for format strings
    {error_location, column},       % Include column in errors
    {feature, maybe_expr, enable}   % Enable experimental features
]}.

src_dirs

Purpose: Source directories to search for .erl files

Type: [Dir :: string()] or [{Dir, Opts}]

Default: ["src"]

Examples:

{src_dirs, ["src", "lib", "core"]}.

{src_dirs, [
    "src",
    {"lib", [{recursive, true}]}
]}.

extra_src_dirs

Purpose: Additional source directories (compiled separately, not in .app modules list)

Type: [Dir :: string()]

Default: []

Common Use: Test, script, example directories

Example:

{extra_src_dirs, ["test", "scripts"]}.

erl_first_files

Purpose: Files to compile before others

Type: [File :: string()]

Use Cases: Parse transforms, macros, type definitions

Example:

{erl_opts, [
    {erl_first_files, ["src/my_transform.erl", "src/types.erl"]}
]}.

validate_app_modules

Purpose: Validate all modules in .app exist as .beam files

Type: boolean()

Default: true

Example:

{validate_app_modules, false}.