From 4823c4f7c792f8a9e4c27744f436f0f10763ef17 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Bj=C3=B6rn=20Gustavsson?= Date: Thu, 21 May 2015 12:23:48 +0200 Subject: Update compiler documentation MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Language cleaned up by the technical writer tmanevik from Combitech. Proofreading and corrections by Björn Gustavsson. --- lib/compiler/doc/src/compile.xml | 506 +++++++++++++++++++-------------------- lib/compiler/doc/src/ref_man.xml | 2 +- 2 files changed, 249 insertions(+), 259 deletions(-) (limited to 'lib/compiler') diff --git a/lib/compiler/doc/src/compile.xml b/lib/compiler/doc/src/compile.xml index 5fccdcdcb5..a271729c82 100644 --- a/lib/compiler/doc/src/compile.xml +++ b/lib/compiler/doc/src/compile.xml @@ -32,15 +32,15 @@ Erlang Compiler

This module provides an interface to the standard Erlang - compiler. It can generate either a new file which contains - the object code, or return a binary which can be loaded directly. + compiler. It can generate either a new file, which contains + the object code, or return a binary, which can be loaded directly.

file(File) - Compile a file + Compiles a file.

Is the same as file(File, [verbose,report_errors,report_warnings]). @@ -50,7 +50,7 @@ file(File, Options) -> CompRet - Compile a file + Compiles a file. CompRet = ModRet | BinRet | ErrRet ModRet = {ok,ModuleName} | {ok,ModuleName,Warnings} @@ -64,39 +64,38 @@

Returns {ok,ModuleName} if successful, or error if there are errors. An object code file is created if - the compilation succeeds with no errors. It is considered + the compilation succeeds without errors. It is considered to be an error if the module name in the source code is not the same as the basename of the output file.

-

Here follows first all elements of Options that in - some way control the behavior of the compiler.

+

Available options:

basic_validation -

This option is fast way to test whether a module will - compile successfully (mainly useful for code generators - that want to verify the code they emit). No code will +

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) will be returned too.

+ variables and functions) are also returned.

-

Use the strong_validation option to generate all +

Use option strong_validation to generate all warnings that the compiler would generate.

 strong_validation -

Similar to the basic_validation option, no code - will be generated, but more compiler passes will be run - to ensure also warnings generated by the optimization - passes are generated (such as clauses that will not match +

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 run-time).

+ exception at runtime).

 binary -

Causes the compiler to return the object code in a +

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

 @@ -105,7 +104,9 @@

The compiler will emit informational warnings about binary matching optimizations (both successful and unsuccessful). - See the Efficiency Guide for further information.

+ For more information, see the section about + bin_opt_info + in the Efficiency Guide.

 compressed @@ -117,20 +118,19 @@ debug_info -

Include debug information in the form of abstract code +

Includes debug information in the form of abstract code (see The Abstract Format in ERTS User's Guide) in the compiled beam module. Tools - such as Debugger, Xref and Cover require the debug - information to be included.

+ such as Debugger, Xref, and Cover require + the debug information to be included.

Warning: Source code can be reconstructed from the debug information. Use encrypted debug information - (see below) to prevent this.

+ (encrypt_debug_info) to prevent this.

-

See - beam_lib(3) - for details.

+

For details, see + beam_lib(3).

 {debug_info_key,KeyString} @@ -138,65 +138,61 @@ {debug_info_key,{Mode,KeyString}} -

Include debug information, but encrypt it, so that it +

Includes debug information, but encrypts it so that it cannot be accessed without supplying the key. (To give - the debug_info option as well is allowed, but is + option debug_info as well is allowed, but not necessary.) Using this option is a good way to always have the debug information available during testing, yet - protect the source code.

+ protecting the source code.

Mode is the type of crypto algorithm to be used - for encrypting the debug information. The default type -- - and currently the only type -- is des3_cbc.

-

See - beam_lib(3) - for details.

+ for encrypting the debug information. The default + (and currently the only) type is des3_cbc.

+

For details, see + beam_lib(3).

 encrypt_debug_info -

Like the debug_info_key option above, except that - the key will be read from an .erlang.crypt file. +

Similar to the debug_info_key option, but + the key is read from an .erlang.crypt file.

-

See - beam_lib(3) - for details.

+

For details, see + beam_lib(3).

 makedep -

Produce a Makefile rule to track headers dependencies. +

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

By default, this rule is written to - .Pbeam]]>. However, if the option + .Pbeam]]>. However, if option binary is set, nothing is written and the rule is returned in Binary.

-

For instance, if one has the following module: +

For example, if you have the following module:

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

Here is the Makefile rule generated by this option: +-include("header.hrl"). +

The Makefile rule generated by this option looks as follows:

module.beam: module.erl \ /usr/local/lib/erlang/lib/eunit/include/eunit.hrl \ - header.hrl - + header.hrl {makedep_output, Output} -

Write generated rule(s) to Output instead of the +

Writes generated rules to Output instead of the default .Pbeam]]>. Output can be a filename or an io_device(). To write to - stdout, use standard_io. However if binary + 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}. @@ -205,7 +201,7 @@ module.beam: module.erl \ {makedep_target, Target} -

Change the name of the rule emitted to Target. +

Changes the name of the rule emitted to Target.

@@ -217,20 +213,20 @@ module.beam: module.erl \ makedep_add_missing -

Consider missing headers as generated files and add them to the +

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

makedep_phony -

Add a phony target for each dependency. +

Adds a phony target for each dependency.

'P' -

Produces a listing of the parsed code after preprocessing +

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

@@ -238,7 +234,7 @@ module.beam: module.erl \ 'E' -

Produces a listing of the code after all source code +

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

@@ -258,21 +254,21 @@ module.beam: module.erl \ report -

This is a short form for both report_errors and +

A short form for both report_errors and report_warnings.

 return_errors -

If this flag is set, then +

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

 return_warnings -

If this flag is set, then an extra field containing - WarningList is added to the tuples returned on +

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

 @@ -284,13 +280,13 @@ module.beam: module.erl \ return -

This is a short form for both return_errors and +

A short form for both return_errors and return_warnings.

 verbose -

Causes more verbose information from the compiler +

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

 @@ -314,7 +310,7 @@ module.beam: module.erl \ {i,Dir} -

Add Dir to the list of directories to be searched +

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 @@ -322,14 +318,14 @@ module.beam: module.erl \

".", the current working directory of - the file server;

+ the file server

 -

the base name of the compiled file;

+

The base name of the compiled file

 -

the directories specified using the i option. - The directory specified last is searched first.

+

The directories specified using option i; + the directory specified last is searched first

 @@ -353,15 +349,15 @@ module.beam: module.erl \ from_asm

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

+ 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"). Note that the format of core files - is not documented, and may change between releases.

+ file suffix ".core"). Notice that the format of core files + is not documented, and can change between releases.

 no_strict_record_tests @@ -369,9 +365,9 @@ module.beam: module.erl \

This option is not recommended.

By default, the generated code for - the Record#record_tag.field operation verifies that - the tuple Record is of the correct size for - the record and that the first element is the tag + operation Record#record_tag.field verifies that + the tuple Record has the correct size for + the record, and that the first element is the tag record_tag. Use this option to omit the verification code.

 @@ -390,79 +386,87 @@ module.beam: module.erl \ {no_auto_import,[{F,A}, ...]}

Makes the function F/A no longer being - auto-imported from the module erlang, which resolves - BIF name clashes. This option has to be used to resolve name - clashes with BIFs auto-imported before R14A, if one wants to + 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.

-

From R14A and forward, the compiler resolves calls +

As from R14A and forward, the compiler resolves calls without module prefix to local or imported functions before - trying auto-imported BIFs. If the BIF is to be + trying with auto-imported BIFs. If the BIF is to be called, use the erlang module prefix in the call, not - { no_auto_import,[{F,A}, ...]}

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

If this option is written in the source code, as a -compile directive, the syntax F/A can be used instead - of {F,A}. Example:

+ of {F,A}, for example:

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

Do not auto import any functions from the module erlang.

+

Do not auto-import any functions from erlang module.

 no_line_info -

Omit line number information in order to produce a slightly +

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

-

If warnings are turned on (the report_warnings option - described above), the following options control what type of - warnings that will be generated. +

If warnings are turned on (option report_warnings + described earlier), the following options control what type of + warnings that are generated. - With the exception of {warn_format,Verbosity} all - options below have two forms; one warn_xxx form to - turn on the warning and one nowarn_xxx form to turn off - the warning. In the description that follows, the form that - is used to change the default value is listed.

+ Except from {warn_format,Verbosity}, the following options + have two forms:

+ + A warn_xxx form, to turn on the warning. + A nowarn_xxx form, to turn off the warning. + +

In the descriptions that follow, the form that is used to change + the default value are listed.

{warn_format, Verbosity}

Causes warnings to be emitted for malformed format strings as arguments to io:format and similar - functions. Verbosity selects the amount of - warnings: 0 = no warnings; 1 = warnings for invalid - format strings and incorrect number of arguments; 2 = - warnings also when the validity could not be checked - (for example, when the format string argument is a - variable). The default verbosity is 1. Verbosity 0 can - also be selected by the option nowarn_format.

+ functions.

+

Verbosity selects the number of warnings:

+ + 0 = No warnings + 1 = Warnings for invalid format strings and incorrect + number of arguments + 2 = Warnings also when the validity cannot + be checked, for example, when the format string argument is a + variable. + +

The default verbosity is 1. Verbosity 0 can + also be selected by option nowarn_format.

 nowarn_bif_clash -

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

+

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

-

Beginning with R14A, the compiler no longer calls the +

As from beginning with R14A, the compiler no longer calls the auto-imported BIF if the name clashes with a local or - explicitly imported function and a call without explicit - module name is issued. Instead the local or imported - function is called. Still accepting nowarn_bif_clash would makes a - module calling functions clashing with autoimported BIFs + explicitly imported function, and a call without explicit + module name is issued. Instead, the local or imported + function is called. Still accepting nowarn_bif_clash would + make a module calling functions clashing with auto-imported BIFs compile with both the old and new compilers, but with - completely different semantics, why the option was removed.

+ completely different semantics. This is why the option is removed.

-

The use of this option has always been strongly discouraged. - From OTP R14A and forward it's an error to use it.

+

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.

 @@ -470,11 +474,11 @@ module.beam: module.erl \ {nowarn_bif_clash, FAs} -

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

+

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

-

The use of this option has always been strongly discouraged. - From OTP R14A and forward it's an error to use it.

+

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.

 @@ -482,35 +486,29 @@ module.beam: module.erl \ warn_export_all -

Causes a warning to be emitted if the export_all - option has also been given.

+

Emits a warning if option export_all is also given.

 warn_export_vars -

Causes warnings to be emitted for all implicitly - exported variables referred to after the primitives - where they were first defined. No warnings for exported - variables unless they are referred to in some pattern, - which is the default, can be selected by the option - nowarn_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.

 - warn_shadow_vars + nowarn_shadow_vars -

Causes warnings to be emitted for "fresh" variables - in functional objects or list comprehensions with the same - name as some already defined variable. The default is to - warn for such variables. No warnings for shadowed - variables can be selected by the option - 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.

 nowarn_unused_function -

Turns off warnings for unused local functions. - By default (warn_unused_function), warnings are - emitted for all local functions that are not called +

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 @@ -519,148 +517,142 @@ module.beam: module.erl \ {nowarn_unused_function, FAs} -

Turns off warnings for unused local functions as - nowarn_unused_function but only for the mentioned +

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. By - default (warn_deprecated_function), warnings are - emitted for every call to a function known by the compiler - to be deprecated. Note that the compiler does not know - about the -deprecated() attribute but uses an +

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. + 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 c:xm/1 - function.

+ xref:m/1, also + accessible through the function + c:xm/1.

 {nowarn_deprecated_function, MFAs} -

Turns off warnings for calls to deprecated functions as - nowarn_deprecated_function but only for +

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 uses of deprecated types. By - default (warn_deprecated_type), warnings are - emitted for every use of a type known by the compiler - to be deprecated.

+

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.

 warn_obsolete_guard -

Causes warnings to be emitted for calls to old type - testing BIFs such as pid/1 and list/1. See - the - Erlang Reference Manual +

Emits 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. No warnings for calls to old type testing - BIFs, which is the default, can be selected by the option - nowarn_obsolete_guard.

+ equivalents. Default is to emit no warnings for calls to + old type testing BIFs.

 warn_unused_import -

Causes warnings to be emitted for unused imported - functions. No warnings for unused imported functions, - which is the default, can be selected by the option - nowarn_unused_import.

+

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

 nowarn_unused_vars -

By default, warnings are emitted for variables which - are not used, with the exception of variables beginning - with an underscore ("Prolog style warnings"). +

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 warnings.

 nowarn_unused_record -

Turns off warnings for unused record types. By - default (warn_unused_records), warnings are - emitted for unused locally defined record types.

+

Turns off warnings for unused record types. Default is to + emit warnings for unused locally defined record types.

Another class of warnings is generated by the compiler during optimization and code generation. They warn about patterns that will never match (such as a=b), guards - that will always evaluate to false, and expressions that will + that always evaluate to false, and expressions that always fail (such as atom+42).

- -

Note that the compiler does not warn for expressions that it - does not attempt to optimize. For instance, the compiler tries - to evaluate 1/0, notices that it will cause an - exception and emits a warning. On the other hand, - the compiler is silent about the similar expression - X/0; because of the variable in it, the compiler does - not even try to evaluate and therefore it emits no warnings. -

- -

Currently, those warnings cannot be disabled (except by +

Those warnings cannot be disabled (except by disabling all warnings).

+ +

The compiler does not warn for expressions that it + does not attempt to optimize. For example, the compiler tries + to evaluate 1/0, detects that it will cause an + exception, and emits a warning. However, + the compiler is silent about the similar expression, + X/0, because of the variable in it. Thus, the compiler does + not even try to evaluate and therefore it emits no warnings.

+ + -

Obviously, the absence of warnings does not mean that +

The absence of warnings does not mean that there are no remaining errors in the code.

 - -

Note that all the options except the include path - ({i,Dir}) can also be given in the file with a - -compile([Option,...]). attribute. - The -compile() attribute is allowed after function + + +

All options, except the include path + ({i,Dir}), can also be given in the file with attribute + -compile([Option,...]). + Attribute -compile() is allowed after the function definitions.

- -

Note also that the {nowarn_unused_function, FAs}, + + + +

The options {nowarn_unused_function, FAs}, {nowarn_bif_clash, FAs}, and - {nowarn_deprecated_function, MFAs} options are only + {nowarn_deprecated_function, MFAs} are only recognized when given in files. They are not affected by - the warn_unused_function, warn_bif_clash, or - warn_deprecated_function options.

+ options warn_unused_function, warn_bif_clash, or + warn_deprecated_function.

+

For debugging of the compiler, or for pure curiosity, the intermediate code generated by each compiler pass can be inspected. - A complete list of the options to produce list files can be - printed by typing compile:options() at the Erlang - shell prompt. - The options will be printed in order that the passes are + To print a complete list of the options to produce list files, + type compile:options() at the Erlang shell prompt. + The options are printed in the order that the passes are executed. If more than one listing option is used, the one representing the earliest pass takes effect.

-

Unrecognized options are ignored.

+

Unrecognized options are ignored.

Both WarningList and ErrorList have the following format:

-[{FileName,[ErrorInfo]}]. - - -

ErrorInfo is described below. The file name has been - included here as the compiler uses the Erlang pre-processor - epp, which allows the code to be included in other - files. For this reason, it is important to know to - which file an error or warning line number refers. +[{FileName,[ErrorInfo]}]. + +

ErrorInfo is described later in this section. + The filename is included here, as the compiler uses the + Erlang pre-processor epp, which allows the code to be + included in other files. It is therefore important to know to + which file the line number of an error or a warning refers.

forms(Forms) - Compile a list of forms + Compiles a list of forms.

Is the same as forms(File, [verbose,report_errors,report_warnings]). @@ -670,7 +662,7 @@ module.beam: module.erl \ forms(Forms, Options) -> CompRet - Compile a list of forms + Compiles a list of forms. Forms = [Form] CompRet = BinRet | ErrRet @@ -681,48 +673,49 @@ module.beam: module.erl \

Analogous to file/1, but takes a list of forms (in the Erlang abstract format representation) as first argument. - The option binary is implicit; i.e., no object code - file is produced. Options that would ordinarily produce a - listing file, such as 'E', will instead cause the internal - format for that compiler pass (an Erlang term; usually not a - binary) to be returned instead of a binary.

+ Option binary is implicit, that is, no object code + file is produced. For options that normally produce a listing + file, such as 'E', the internal format for that compiler pass + (an Erlang term, usually not a binary) is returned instead of + a binary.

 format_error(ErrorDescriptor) -> chars() - Format an error descriptor + Formats an error descriptor. ErrorDescriptor = errordesc()

Uses an ErrorDescriptor and returns a deep list of - characters which describes the error. This function is - usually called implicitly when an ErrorInfo structure - is processed. See below.

+ characters that describes the error. This function is + usually called implicitly when an ErrorInfo structure + (described in section + Error Information) is processed.

 output_generated(Options) -> true | false - Determine whether the compile will generate an output file + Determines whether the compiler generates an output file. Options = [term()] -

Determines whether the compiler would generate a beam +

Determines whether the compiler generates a beam file with the given options. true means that a beam - file would be generated; false means that the compiler - would generate some listing file, return a binary, or merely - check the syntax of the source code.

+ file is generated. false means that the compiler + generates some listing file, returns a binary, or merely + checks the syntax of the source code.

 noenv_file(File, Options) -> CompRet - Compile a file (ignoring ERL_COMPILER_OPTIONS) + Compiles a file (ignoring ERL_COMPILER_OPTIONS). -

Works exactly like file/2, +

Works like file/2, except that the environment variable ERL_COMPILER_OPTIONS is not consulted.

 @@ -730,9 +723,9 @@ module.beam: module.erl \ noenv_forms(Forms, Options) -> CompRet - Compile a list of forms (ignoring ERL_COMPILER_OPTIONS) + Compiles a list of forms (ignoring ERL_COMPILER_OPTIONS). -

Works exactly like forms/2, +

Works like forms/2, except that the environment variable ERL_COMPILER_OPTIONS is not consulted.

 @@ -740,12 +733,13 @@ module.beam: module.erl \ noenv_output_generated(Options) -> true | false - Determine whether the compile will generate an output file (ignoring ERL_COMPILER_OPTIONS) + Determines whether the compiler generates an output file + (ignoring ERL_COMPILER_OPTIONS). Options = [term()] -

Works exactly like +

Works like output_generated/1, except that the environment variable ERL_COMPILER_OPTIONS is not consulted.

@@ -755,14 +749,14 @@ module.beam: module.erl \
- Default compiler options + Default Compiler Options

The (host operating system) environment variable ERL_COMPILER_OPTIONS can be used to give default compiler options. Its value must be a valid Erlang term. If the value is a - list, it will be used as is. If it is not a list, it will be put + list, it is used as is. If it is not a list, it is put into a list.

-

The list will be appended to any options given to +

The list is appended to any options given to file/2, forms/2, and output_generated/2. @@ -770,9 +764,9 @@ module.beam: module.erl \ noenv_file/2, noenv_forms/2, or noenv_output_generated/2 - if you don't want the environment variable to be consulted - (for instance, if you are calling the compiler recursively from - inside a parse transform).

+ if you do not want the environment variable to be consulted, + for example, if you are calling the compiler recursively from + inside a parse transform.

@@ -781,31 +775,31 @@ module.beam: module.erl \ module. Inlining means that a call to a function is replaced with the function body with the arguments replaced with the actual values. The semantics are preserved, except if exceptions are - generated in the inlined code. Exceptions will be reported as + generated in the inlined code. Exceptions are reported as occurring in the function the body was inlined into. Also, - function_clause exceptions will be converted to similar + function_clause exceptions are converted to similar case_clause exceptions.

-

When a function is inlined, the original function will be +

When a function is inlined, the original function is kept if it is exported (either by an explicit export or if the - export_all option was given) or if not all calls to the - function were inlined.

+ option export_all was given) or if not all calls to the + function are inlined.

Inlining does not necessarily improve running time. - For instance, inlining may increase Beam stack usage which will - probably be detrimental to performance for recursive functions. + For example, inlining can increase Beam stack use, which + probably is detrimental to performance for recursive functions.

-

Inlining is never default; it must be explicitly enabled with a +

Inlining is never default. It must be explicitly enabled with a compiler option or a -compile() attribute in the source module.

-

To enable inlining, either use the inline option to - let the compiler decide which functions to inline or +

To enable inlining, either use the option inline to + let the compiler decide which functions to inline, or {inline,[{Name,Arity},...]} to have the compiler inline all calls to the given functions. If the option is given inside a compile directive in an Erlang module, {Name,Arity} - may be written as Name/Arity.

+ can be written as Name/Arity.

Example of explicit inlining:

@@ -817,33 +811,30 @@ pi() -> 3.1416.

Example of implicit inlining:

--compile(inline).
-
+-compile(inline). -

The {inline_size,Size} option controls how large functions - that are allowed to be inlined. Default is 24, which will - keep the size of the inlined code roughly the same as - the un-inlined version (only relatively small functions will be +

The option {inline_size,Size} controls how large functions + that are allowed to be inlined. Default is 24, which + keeps the size of the inlined code roughly the same as + the un-inlined version (only relatively small functions are inlined).

Example:

 %% Aggressive inlining - will increase code size.
 -compile(inline).
--compile({inline_size,100}).
-
+-compile({inline_size,100}).
- Inlining of list functions -

The compiler can also inline a variety of list manipulation functions - from the stdlib's lists module.

+ Inlining of List Functions +

The compiler can also inline various list manipulation functions + from the module list in STDLIB.

This feature must be explicitly enabled with a compiler option or a -compile() attribute in the source module.

-

To enable inlining of list functions, use the inline_list_funcs - option.

+

To enable inlining of list functions, use option inline_list_funcs.

The following functions are inlined:

@@ -869,24 +860,23 @@ pi() -> 3.1416.
+ Error Information -

The ErrorInfo mentioned above is the standard - ErrorInfo structure which is returned from all IO modules. +

The ErrorInfo mentioned earlier is the standard + ErrorInfo structure, which is returned from all I/O modules. It has the following format:

-{ErrorLine, Module, ErrorDescriptor} - +{ErrorLine, Module, ErrorDescriptor} -

ErrorLine will be the atom none if the error does - not correspond to a specific line (e.g. if the source file does - not exist).

+

ErrorLine is the atom none if the error does + not correspond to a specific line, for example, if the source file does + not exist.

A string describing the error is obtained with the following call:

-Module:format_error(ErrorDescriptor) - +Module:format_error(ErrorDescriptor)
diff --git a/lib/compiler/doc/src/ref_man.xml b/lib/compiler/doc/src/ref_man.xml index 6478ad4b11..6584e79c4e 100644 --- a/lib/compiler/doc/src/ref_man.xml +++ b/lib/compiler/doc/src/ref_man.xml @@ -29,7 +29,7 @@ application.sgml -

The Compiler application compiles Erlang +

The Compiler application compiles Erlang code to byte-code. The highly compact byte-code is executed by the Erlang emulator.

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