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<erlref>
  <header>
    <copyright>
      <year>2006</year><year>2010</year>
      <holder>Ericsson AB. All Rights Reserved.</holder>
    </copyright>
    <legalnotice>
      The contents of this file are subject to the Erlang Public License,
      Version 1.1, (the "License"); you may not use this file except in
      compliance with the License. You should have received a copy of the
      Erlang Public License along with this software. If not, it can be
      retrieved online at http://www.erlang.org/.

      Software distributed under the License is distributed on an "AS IS"
      basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
      the License for the specific language governing rights and limitations
      under the License.

    </legalnotice>

    <title>dialyzer</title>
    <prepared></prepared>
    <docno></docno>
    <date></date>
    <rev></rev>
  </header>
  <module>dialyzer</module>
  <modulesummary>The Dialyzer, a DIscrepancy AnalYZer for ERlang programs</modulesummary>
  <description>
    <p>The Dialyzer is a static analysis tool that identifies software
    discrepancies such as definite type errors, code which has become
    dead or unreachable due to some programming error, unnecessary
    tests, etc. in single Erlang modules or entire (sets of)
    applications. Dialyzer starts its analysis from either
    debug-compiled BEAM bytecode or from Erlang source code. The file
    and line number of a discrepancy is reported along with an
    indication of what the discrepancy is about. Dialyzer bases its
    analysis on the concept of success typings which allows for sound
    warnings (no false positives).</p>
    <p>Read more about Dialyzer and about how to use it from the GUI
    in <seealso marker="dialyzer_chapter">Dialyzer User's
    Guide</seealso>.</p>
  </description>

  <section>
    <title>Using the Dialyzer from the command line</title>
    <p>Dialyzer also has a command line version for automated use. Below is a
      brief description of the list of its options. The same information can
      be obtained by writing</p>
    <code type="none"><![CDATA[
      dialyzer --help
    ]]></code>
    <p>in a shell. Please refer to the GUI description for more details on
      the operation of Dialyzer.</p>
    <p>The exit status of the command line version is:</p>
    <code type="none"><![CDATA[
      0 - No problems were encountered during the analysis and no
          warnings were emitted.
      1 - Problems were encountered during the analysis.
      2 - No problems were encountered, but warnings were emitted.
    ]]></code>
    <p>Usage:</p>
    <code type="none"><![CDATA[
   dialyzer [--help] [--version] [--shell] [--quiet] [--verbose]
		[-pa dir]* [--plt plt] [-Ddefine]* [-I include_dir]* 
		[--output_plt file] [-Wwarn]* [--src] 
		[-c applications] [-r applications] [-o outfile]
		[--build_plt] [--add_to_plt] [--remove_from_plt]
		[--check_plt] [--no_check_plt] [--plt_info] [--get_warnings]
    ]]></code>
    <p>Options:</p>
    <taglist>
      <tag><c><![CDATA[-c applications]]></c>(or <c><![CDATA[--command-line applications]]></c>)</tag>
      <item>use Dialyzer from the command line (no GUI) to detect defects in the
       specified applications (directories or <c><![CDATA[.erl]]></c> or <c><![CDATA[.beam]]></c> files)</item>
      <tag><c><![CDATA[-r applications]]></c></tag>
      <item>same as <c><![CDATA[-c]]></c> only that directories are searched recursively for 
       subdirectories containing <c><![CDATA[.erl]]></c> or <c><![CDATA[.beam]]></c> files (depending on the 
       type of analysis)</item>
      <tag><c><![CDATA[-o outfile]]></c>(or <c><![CDATA[--output outfile]]></c>)</tag>
      <item>when using Dialyzer from the command line, send the analysis
       results in the specified <c><![CDATA[outfile]]></c> rather than in stdout</item>
      <tag><c><![CDATA[--src]]></c></tag>
      <item>override the default, which is to analyze debug compiled BEAM 
       bytecode, and analyze starting from Erlang source code instead</item>
      <tag><c><![CDATA[--raw]]></c></tag>
      <item>When using Dialyzer from the command line, output the raw analysis
       results (Erlang terms) instead of the formatted result.
       The raw format is easier to post-process (for instance, to filter
       warnings or to output HTML pages).</item>
      <tag><c><![CDATA[-Dname]]></c>(or <c><![CDATA[-Dname=value]]></c>)</tag>
      <item>when analyzing from source, pass the define to Dialyzer (**)</item>
      <tag><c><![CDATA[-I include_dir]]></c></tag>
      <item>when analyzing from source, pass the <c><![CDATA[include_dir]]></c> to Dialyzer (**)</item>
      <tag><c><![CDATA[-pa dir]]></c></tag>
      <item>Include <c><![CDATA[dir]]></c> in the path for Erlang. Useful when analyzing files
       that have <c><![CDATA[-include_lib()]]></c> directives.</item>
      <tag><c><![CDATA[--output_plt file]]></c></tag>
      <item>Store the PLT at the specified location after building it.</item>
      <tag><c><![CDATA[--plt plt]]></c></tag>
      <item>Use the specified plt as the initial persistent lookup table.</item>
      <tag><c><![CDATA[-Wwarn]]></c></tag>
      <item>a family of option which selectively turn on/off warnings.
       (for help on the names of warnings use <c><![CDATA[dialyzer -Whelp]]></c>)</item>
      <tag><c><![CDATA[--shell]]></c></tag>
      <item>do not disable the Erlang shell while running the GUI</item>
      <tag><c><![CDATA[--version (or -v)]]></c></tag>
      <item>prints the Dialyzer version and some more information and exits</item>
      <tag><c><![CDATA[--help (or -h)]]></c></tag>
      <item>prints this message and exits</item>
      <tag><c><![CDATA[--quiet (or -q)]]></c></tag>
      <item>makes Dialyzer a bit more quiet</item>
      <tag><c><![CDATA[--verbose]]></c></tag>
      <item>makes Dialyzer a bit more verbose</item>
      <tag><c><![CDATA[--check_plt]]></c></tag>
      <item>Only checks if the initial PLT is up to date and rebuilds it if this is not the case</item>
      <tag><c><![CDATA[--no_check_plt (or -n)]]></c></tag>
      <item>Skip the PLT integrity check when running Dialyzer.
       Useful when working with installed PLTs that never change.</item>
      <tag><c><![CDATA[--build_plt]]></c></tag>
      <item>The analysis starts from an empty PLT and creates a new one from
       the files specified with -c and -r. Only works for beam files.
       Use --plt or --output_plt to override the default PLT location.</item>
      <tag><c><![CDATA[--add_to_plt]]></c></tag>   
      <item> The PLT is extended to also include the files specified with 
       -c and -r. Use --plt to specify which PLT to start from, and --output_plt 
       to specify where to put the PLT. Note that the analysis might include 
       files from the PLT if they depend on the new files. 
       This option only works with beam files.</item>
       <tag><c><![CDATA[--remove_from_plt]]></c></tag>
       <item>The information from the files specified with -c and -r is removed
       from the PLT. Note that this may cause a re-analysis of the remaining
       dependent files.</item>
       <tag><c><![CDATA[--get_warnings]]></c></tag>
       <item>Makes Dialyzer emit warnings even when manipulating the PLT. Only 
       emits warnings for files that are actually analyzed. The default is to
       not emit any warnings when manipulating the PLT. This option has no 
       effect when performing a normal analysis.</item>
    </taglist>
    <note>
      <p>* denotes that multiple occurrences of these options are possible.</p>
      <p>** options <c><![CDATA[-D]]></c> and <c><![CDATA[-I]]></c> work both from command-line and in the Dialyzer GUI;
        the syntax of defines and includes is the same as that used by <c><![CDATA[erlc]]></c>.</p>
    </note>
    <p>Warning options:</p>
    <taglist>
      <tag><c><![CDATA[-Wno_return]]></c></tag>
      <item>Suppress warnings for functions of no return.</item>
      <tag><c><![CDATA[-Wno_unused]]></c></tag>
      <item>Suppress warnings for unused functions.</item>
      <tag><c><![CDATA[-Wno_improper_lists]]></c></tag>
      <item>Suppress warnings for construction of improper lists.</item>
      <tag><c><![CDATA[-Wno_fun_app]]></c></tag>
      <item>Suppress warnings for fun applications that will fail.</item>
      <tag><c><![CDATA[-Wno_match]]></c></tag>
      <item>Suppress warnings for patterns that are unused or cannot
       match.</item>
      <tag><c><![CDATA[-Werror_handling]]></c>***</tag>
      <item>Include warnings for functions that only return by means of an
       exception.</item>
      <tag><c><![CDATA[-Wunmatched_returns]]></c>***</tag>
      <item>Include warnings for function calls which ignore a structured return
       value or do not match against one of many possible return value(s).</item>
      <tag><c><![CDATA[-Wunderspecs]]></c>***</tag>
      <item>Warn about underspecified functions 
      (the -spec is strictly more allowing than the success typing)</item>
      <tag><c><![CDATA[-Woverspecs]]></c>***</tag>
      <item>Warn about overspecified functions 
      (the -spec is strictly less allowing than the success typing)</item>
      <tag><c><![CDATA[-Wspecdiffs]]></c>***</tag>
      <item>Warn when the -spec is different than the success typing</item>
    </taglist>
    <note>
      <p>*** These are options that turn on warnings rather than
      turning them off.</p>
    </note>
  </section>

  <section>
    <title>Using the Dialyzer from Erlang</title>
    <p>You can also use Dialyzer directly from Erlang. Both the GUI and the
      command line versions are available. The options are similar to the ones
      given from the command line, so please refer to the sections above for
      a description of these.</p>
  </section>
  <funcs>
    <func>
      <name>gui() -> ok | {error, Msg}</name>
      <name>gui(OptList) -> ok | {error, Msg}</name>
      <fsummary>Dialyzer GUI version</fsummary>
      <type>
        <v>OptList -- see below</v>
      </type>
      <desc>
        <p>Dialyzer GUI version.</p>
        <code type="none"><![CDATA[
OptList  : [Option]
Option   : {files,          [Filename : string()]}
         | {files_rec,      [DirName : string()]}
         | {defines,        [{Macro: atom(), Value : term()}]}
         | {from,           src_code | byte_code} %% Defaults to byte_code
         | {init_plt,       FileName : string()}  %% If changed from default
         | {include_dirs,   [DirName : string()]} 
         | {output_file,    FileName : string()}
         | {output_plt,     FileName :: string()}
         | {analysis_type,  'succ_typings' | 'plt_add' | 'plt_build' | 'plt_check' | 'plt_remove'}
         | {warnings,       [WarnOpts]}
         | {get_warnings,   bool()}

WarnOpts : no_return
         | no_unused
         | no_improper_lists
         | no_fun_app
         | no_match
         | no_fail_call
         | error_handling
         | unmatched_returns
         | overspecs
         | underspecs
         | specdiffs
        ]]></code>
      </desc>
    </func>
    <func>
      <name>run(OptList) -> Warnings</name>
      <fsummary>Dialyzer command line version</fsummary>
      <type>
        <v>OptList -- see gui/0,1</v>
        <v>Warnings -- see below </v>
      </type>
      <desc>
        <p>Dialyzer command line version.</p>
        <code type="none"><![CDATA[
Warnings :: [{Tag, Id, Msg}]
Tag : 'warn_return_no_exit' | 'warn_return_only_exit'
    | 'warn_not_called' | 'warn_non_proper_list'
    | 'warn_fun_app' | 'warn_matching'
    | 'warn_failing_call' | 'warn_contract_types'
    | 'warn_contract_syntax' | 'warn_contract_not_equal'
    | 'warn_contract_subtype' | 'warn_contract_supertype'
Id = {File :: string(), Line :: integer()}
Msg = msg() -- Undefined
]]></code>
      </desc>
    </func>
    <func>
      <name>format_warning(Msg) -> string()</name>
      <fsummary>Get the string version of a warning message.</fsummary>
      <type>
        <v>Msg = {Tag, Id, msg()} -- See run/1</v>
      </type>
      <desc>
        <p>Get a string from warnings as returned by dialyzer:run/1.</p>
      </desc>
    </func>
    <func>
      <name>plt_info(string()) -> {'ok', [{atom(), any()}]} | {'error', atom()}</name>
      <fsummary>Returns information about the specified plt.</fsummary>
      <desc>
        <p>Returns information about the specified plt.</p>
      </desc>
    </func>
  </funcs>
</erlref>
