-spec all_chunks(beam()) -> {ok, module(), [{chunkid(), dataB()}]} | {error, beam_lib, info_rsn()}.

Reads chunk data for all chunks.

-spec build_module(Chunks) -> {ok, Binary} when Chunks :: [{chunkid(), dataB()}], Binary :: binary().

Builds a BEAM module (as a binary) from a list of chunks.

-spec chunks(Beam, ChunkRefs) -> {ok, {module(), [chunkdata()]}} | {error, beam_lib, chnk_rsn()}
          when Beam :: beam(), ChunkRefs :: [chunkref()].

Reads chunk data for selected chunks references. The order of the returned list of chunk data is determined by the order of the list of chunks references.

-spec chunks(Beam, ChunkRefs, Options) ->
          {ok, {module(), [ChunkResult]}} | {error, beam_lib, chnk_rsn()}
          when
              Beam :: beam(),
              ChunkRefs :: [chunkref()],
              Options :: [allow_missing_chunks],
              ChunkResult :: chunkdata() | {ChunkRef :: chunkref(), missing_chunk}.

Reads chunk data for selected chunks references. The order of the returned list of chunk data is determined by the order of the list of chunks references.

By default, if any requested chunk is missing in Beam, an error tuple is returned. However, if option allow_missing_chunks is specified, a result is returned even if chunks are missing. In the result list, any missing chunks are represented as {ChunkRef,missing_chunk}. Notice however that if chunk "Atom" is missing, that is considered a fatal error and the return value is an error tuple.

-spec clear_crypto_key_fun() -> undefined | {ok, Result} when Result :: undefined | term().

Unregisters the crypto key fun and terminates the process holding it, started by crypto_key_fun/1.

Returns either {ok, undefined} if no crypto key fun is registered, or {ok, Term}, where Term is the return value from CryptoKeyFun(clear), see crypto_key_fun/1.

-spec cmp(Beam1, Beam2) -> ok | {error, beam_lib, cmp_rsn()} when Beam1 :: beam(), Beam2 :: beam().

Compares the contents of two BEAM files.

If the module names are the same, and all chunks except for chunk "CInf" (the chunk containing the compilation information that is returned by Module:module_info(compile)) have the same contents in both files, ok is returned. Otherwise an error message is returned.

-spec cmp_dirs(Dir1, Dir2) -> {Only1, Only2, Different} | {error, beam_lib, Reason}
            when
                Dir1 :: atom() | file:filename(),
                Dir2 :: atom() | file:filename(),
                Only1 :: [file:filename()],
                Only2 :: [file:filename()],
                Different :: [{Filename1 :: file:filename(), Filename2 :: file:filename()}],
                Reason :: {not_a_directory, term()} | info_rsn().

Compares the BEAM files in two directories.

Only files with extension ".beam" are compared. BEAM files that exist only in directory Dir1 (Dir2) are returned in Only1 (Only2). BEAM files that exist in both directories but are considered different by cmp/2 are returned as pairs {Filename1, Filename2}, where Filename1 (Filename2) exists in directory Dir1 (Dir2).

-spec crypto_key_fun(CryptoKeyFun) -> ok | {error, Reason}
                  when CryptoKeyFun :: crypto_fun(), Reason :: badfun | exists | term().

Registers an unary fun that is called if beam_lib must read an debug_info chunk that has been encrypted. The fun is held in a process that is started by the function.

If a fun is already registered when attempting to register a fun, {error, exists} is returned.

The fun must handle the following arguments:

CryptoKeyFun(init) -> ok | {ok, NewCryptoKeyFun} | {error, Term}

Called when the fun is registered, in the process that holds the fun. Here the crypto key fun can do any necessary initializations. If {ok, NewCryptoKeyFun} is returned, NewCryptoKeyFun is registered instead of CryptoKeyFun. If {error, Term} is returned, the registration is aborted and crypto_key_fun/1 also returns {error, Term}.

CryptoKeyFun({debug_info, Mode, Module, Filename}) -> Key

Called when the key is needed for module Module in the file named Filename. Mode is the type of crypto algorithm; currently, the only possible value is des3_cbc. The call is to fail (raise an exception) if no key is available.

CryptoKeyFun(clear) -> term()

Called before the fun is unregistered. Here any cleaning up can be done. The return value is not important, but is passed back to the caller of clear_crypto_key_fun/0 as part of its return value.

-spec diff_dirs(Dir1, Dir2) -> ok | {error, beam_lib, Reason}
             when
                 Dir1 :: atom() | file:filename(),
                 Dir2 :: atom() | file:filename(),
                 Reason :: {not_a_directory, term()} | info_rsn().

Compares the BEAM files in two directories as cmp_dirs/2, but the names of files that exist in only one directory or are different are presented on standard output.

-spec format_error(Reason) -> io_lib:chars() when Reason :: term().

For a specified error returned by any function in this module, this function returns a descriptive string of the error in English. For file errors, function file:format_error(Posix) is to be called.

-spec info(Beam) -> [InfoPair] | {error, beam_lib, info_rsn()}
        when
            Beam :: beam(),
            InfoPair ::
                {file, Filename :: file:filename()} |
                {binary, Binary :: binary()} |
                {module, Module :: module()} |
                {chunks,
                 [{ChunkId :: chunkid(), Pos :: non_neg_integer(), Size :: non_neg_integer()}]}.

Returns a list containing some information about a BEAM file as tuples {Item, Info}:

• {file, Filename} | {binary, Binary} - The name (string) of the BEAM file, or the binary from which the information was extracted.

• {module, Module} - The name (atom) of the module.

• {chunks, [{ChunkId, Pos, Size}]} - For each chunk, the identifier (string) and the position and size of the chunk data, in bytes.

-spec md5(Beam) -> {ok, {module(), MD5}} | {error, beam_lib, chnk_rsn()}
       when Beam :: beam(), MD5 :: binary().

Calculates an MD5 redundancy check for the code of the module (compilation date and other attributes are not included).

-spec strip(Beam1) -> {ok, {module(), Beam2}} | {error, beam_lib, info_rsn()}
         when Beam1 :: beam(), Beam2 :: beam().

Removes all chunks from a BEAM file except those used by the loader.

In particular, the debug information (chunk debug_info and abstract_code) is removed.

-spec strip(Beam1, AdditionalChunks) -> {ok, {module(), Beam2}} | {error, beam_lib, info_rsn()}
         when Beam1 :: beam(), AdditionalChunks :: [chunkid()], Beam2 :: beam().

Removes all chunks from a BEAM file except those used by the loader or mentioned in AdditionalChunks.

In particular, the debug information (chunk debug_info and abstract_code) is removed.

-spec strip_files(Files) -> {ok, [{module(), Beam}]} | {error, beam_lib, info_rsn()}
               when Files :: [beam()], Beam :: beam().

Removes all chunks except those used by the loader from Files.

In particular, the debug information (chunk debug_info and abstract_code) is removed. The returned list contains one element for each specified filename, in the same order as in Files.

-spec strip_files(Files, AdditionalChunks) -> {ok, [{module(), Beam}]} | {error, beam_lib, info_rsn()}
               when Files :: [beam()], AdditionalChunks :: [chunkid()], Beam :: beam().

Removes all chunks except those used by the loader or mentioned in AdditionalChunks from Files.

In particular, the debug information (chunk debug_info and abstract_code) is removed. The returned list contains one element for each specified filename, in the same order as in Files.

-spec strip_release(Dir) -> {ok, [{module(), file:filename()}]} | {error, beam_lib, Reason}
                 when
                     Dir :: atom() | file:filename(),
                     Reason :: {not_a_directory, term()} | info_rsn().

Removes all chunks except those used by the loader from the BEAM files of a release.

Dir is to be the installation root directory. For example, the current OTP release can be stripped with the call beam_lib:strip_release(code:root_dir()).

-spec strip_release(Dir, AdditionalChunks) ->
                 {ok, [{module(), file:filename()}]} | {error, beam_lib, Reason}
                 when
                     Dir :: atom() | file:filename(),
                     AdditionalChunks :: [chunkid()],
                     Reason :: {not_a_directory, term()} | info_rsn().

Removes all chunks except those used by the loader or mentioned in AdditionalChunks.

Dir is to be the installation root directory. For example, the current OTP release can be stripped with the call beam_lib:strip_release(code:root_dir(),[documentation]).

-spec version(Beam) -> {ok, {module(), [Version :: term()]}} | {error, beam_lib, chnk_rsn()}
           when Beam :: beam().

Returns the module version or versions. A version is defined by module attribute -vsn(Vsn).

If this attribute is not specified, the version defaults to the checksum of the module. Notice that if version Vsn is not a list, it is made into one, that is {ok,{Module,[Vsn]}} is returned. If there are many -vsn module attributes, the result is the concatenated list of versions.

Examples:

1> beam_lib:version(a). % -vsn(1).
{ok,{a,[1]}}
2> beam_lib:version(b). % -vsn([1]).
{ok,{b,[1]}}
3> beam_lib:version(c). % -vsn([1]). -vsn(2).
{ok,{c,[1,2]}}
4> beam_lib:version(d). % no -vsn attribute
{ok,{d,[275613208176997377698094100858909383631]}}