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diff --git a/system/doc/system_principles/system_principles.xml b/system/doc/system_principles/system_principles.xml index 79ed86cd9f..5718e8a3f6 100644 --- a/system/doc/system_principles/system_principles.xml +++ b/system/doc/system_principles/system_principles.xml @@ -28,35 +28,41 @@ <rev></rev> <file>system_principles.xml</file> </header> + <marker id="system principles"></marker> <section> <title>Starting the System</title> - <p>An Erlang runtime system is started with the command <c>erl</c>:</p> + <p>An Erlang runtime system is started with command <c>erl</c>:</p> <pre> % <input>erl</input> Erlang/OTP 17 [erts-6.0] [hipe] [smp:8:8] Eshell V6.0 (abort with ^G) 1> </pre> - <p><c>erl</c> understands a number of command line arguments, see - <c>erl(1)</c>. A number of them are also described in this chapter.</p> - <p>Application programs can access the values of the command line - arguments by calling one of the functions - <c>init:get_argument(Key)</c>, or <c>init:get_arguments()</c>. - See <c>init(3)</c>.</p> + <p><c>erl</c> understands a number of command-line arguments, see + the <seealso marker="erts:erl">erl(1)</seealso> manual page in + ERTS. Some of them are also described in this chapter.</p> + <p>Application programs can access the values of the command-line + arguments by calling the function <c>init:get_argument(Key)</c> + or <c>init:get_arguments()</c>. See the + <seealso marker="erts:init">init(3)</seealso> manual page in + ERTS.</p> </section> <section> <title>Restarting and Stopping the System</title> - <p>The runtime system can be halted by calling <c>halt/0,1</c>. - See <c>erlang(3)</c>.</p> - <p>The module <c>init</c> contains function for restarting, - rebooting and stopping the runtime system. See <c>init(3)</c>.</p> + <p>The runtime system is halted by calling <c>halt/0,1</c>. For + details, see the <seealso marker="erts:erlang">erlang(3)</seealso> + manual page in ERTS.</p> + <p>The module <c>init</c> contains functions for restarting, + rebooting, and stopping the runtime system:</p> <pre> init:restart() init:reboot() init:stop()</pre> - <p>Also, the runtime system will terminate if the Erlang shell is + <p>For details, see the <seealso marker="erts:init">init(3)</seealso> + manual page in ERTS.</p> + <p>The runtime system terminates if the Erlang shell is terminated.</p> </section> @@ -69,14 +75,15 @@ init:stop()</pre> <p>A boot script file has the extension <c>.script</c>. The runtime system uses a binary version of the script. This <em>binary boot script</em> file has the extension <c>.boot</c>.</p> - <p>Which boot script to use is specified by the command line flag - <c>-boot</c>. The extension <c>.boot</c> should be omitted. - Example, using the boot script <c>start_all.boot</c>:</p> + <p>Which boot script to use is specified by the command-line flag + <c>-boot</c>. The extension <c>.boot</c> is to be omitted. + For example, using the boot script <c>start_all.boot</c>:</p> <pre> % <input>erl -boot start_all</input></pre> <p>If no boot script is specified, it defaults to - <c>ROOT/bin/start</c>, see Default Boot Scripts below.</p> - <p>The command line flag <c>-init_debug</c> makes the <c>init</c> + <c>ROOT/bin/start</c>, see <seealso marker="#default_boot_scripts"> + Default Boot Scripts</seealso>.</p> + <p>The command-line flag <c>-init_debug</c> makes the <c>init</c> process write some debug information while interpreting the boot script:</p> <pre> @@ -87,59 +94,55 @@ init:stop()</pre> {start,heart} {start,error_logger} ...</pre> - <p>See <c>script(4)</c> for a detailed description of the syntax - and contents of the boot script.</p> + <p>For a detailed description of the syntax and contents of the + boot script, see the <c>script(4)</c> manual page in SASL.</p> <section> + <marker id="default_boot_scripts"></marker> <title>Default Boot Scripts</title> - <p>Erlang/OTP comes with two boot scripts:</p> - <taglist> - <tag><c>start_clean.boot</c></tag> - <item> - <p>Loads the code for and starts the applications Kernel and - STDLIB.</p> - </item> - <tag><c>start_sasl.boot</c></tag> - <item> - <p>Loads the code for and starts the applications Kernel, - STDLIB and SASL.</p> - </item> - <tag><c>no_dot_erlang.boot</c></tag> - <item> - <p>Loads the code for and starts the applications Kernel and - STDLIB, skips loading the <c>.erlang</c> file. - Useful for scripts and other tools that should be behave the - same regardless of user preferences. - </p> - </item> - </taglist> + <p>Erlang/OTP comes with these boot scripts:</p> + <list type="bulleted"> + <item><c>start_clean.boot</c> - Loads the code for and starts + the applications Kernel and STDLIB.</item> + <item><c>start_sasl.boot</c> - Loads the code for and starts + the applications Kernel, STDLIB, and + SASL).</item> + <item><c>no_dot_erlang.boot</c> - Loads the code for and + starts the applications Kernel and STDLIB. + Skips loading the file <c>.erlang</c>. Useful for scripts and + other tools that are to behave the same irrespective of user + preferences.</item> + </list> <p>Which of <c>start_clean</c> and <c>start_sasl</c> to use as default is decided by the user when installing Erlang/OTP using <c>Install</c>. The user is asked "Do you want to use a minimal system startup instead of the SASL startup". If the answer is yes, then <c>start_clean</c> is used, otherwise - <c>start_sasl</c> is used. A copy of the selected boot script - is made, named <c>start.boot</c> and placed in - the <c>ROOT/bin</c> directory.</p> + <c>start_sasl</c> is used. A copy of the selected boot script is + made, named <c>start.boot</c> and placed in directory + <c>ROOT/bin</c>.</p> </section> <section> <title>User-Defined Boot Scripts</title> <p>It is sometimes useful or necessary to create a user-defined boot script. This is true especially when running Erlang in - embedded mode, see <seealso marker="#code_loading">Code Loading Strategy</seealso>.</p> - <p>It is possible to write a boot script manually. - The recommended way to create a boot script, however, is to - generate the boot script from a release resource file - <c>Name.rel</c>, using the function + embedded mode, see <seealso marker="#code_loading"> + Code Loading Strategy</seealso>.</p> + <p>A boot script can be written manually. However, it is + recommended to create a boot script by generating it from a + release resource file <c>Name.rel</c>, using the function <c>systools:make_script/1,2</c>. This requires that the source code is structured as applications according to the OTP design principles. (The program does not have to be started in terms of - OTP applications but can be plain Erlang).</p> - <p>Read more about <c>.rel</c> files in OTP Design Principles and - <c>rel(4)</c>.</p> + OTP applications, but can be plain Erlang).</p> + <p>For more information about <c>.rel</c> files, see + <seealso marker="otp design principles"> + OTP Design Principles</seealso> and the + <seealso marker="sasl:rel">rel(4)</seealso> manual page in + SASL.</p> <p>The binary boot script file <c>Name.boot</c> is generated from - the boot script file <c>Name.script</c> using the function + the boot script file <c>Name.script</c>, using the function <c>systools:script2boot(File)</c>.</p> </section> </section> @@ -148,16 +151,17 @@ init:stop()</pre> <marker id="code_loading"></marker> <title>Code Loading Strategy</title> <p>The runtime system can be started in either <em>embedded</em> or - <em>interactive</em> mode. Which one is decided by the command - line flag <c>-mode</c>.</p> + <em>interactive</em> mode. Which one is decided by the + command-line flag <c>-mode</c>.</p> <pre> % <input>erl -mode embedded</input></pre> <p>Default mode is <c>interactive</c>.</p> + <p>The mode properties are as follows:</p> <list type="bulleted"> - <item>In embedded mode, all code is loaded during system start-up + <item>In embedded mode, all code is loaded during system startup according to the boot script. (Code can also be loaded later - by explicitly ordering the code server to do so).</item> - <item>In interactive mode, code is dynamically loaded when first + by explicitly ordering the code server to do so.)</item> + <item>In interactive mode, the code is dynamically loaded when first referenced. When a call to a function in a module is made, and the module is not loaded, the code server searches the code path and loads the module into the system.</item> @@ -165,21 +169,21 @@ init:stop()</pre> <p>Initially, the code path consists of the current working directory and all object code directories under <c>ROOT/lib</c>, where <c>ROOT</c> is the installation directory - of Erlang/OTP. Directories can be named <c>Name[-Vsn]</c> and - the code server, by default, chooses the directory with + of Erlang/OTP. Directories can be named <c>Name[-Vsn]</c>. The + code server, by default, chooses the directory with the highest version number among those which have the same <c>Name</c>. The <c>-Vsn</c> suffix is optional. If an <c>ebin</c> directory exists under the <c>Name[-Vsn]</c> - directory, it is this directory which is added to the code path.</p> - <p>The code path can be extended by using the command line flags - <c>-pa Directories</c> and <c>-pz Directories</c>. These will add - <c>Directories</c> to the head or end of the code path, - respectively. Example</p> + directory, this directory is added to the code path.</p> + <p>The code path can be extended by using the command-line flags + <c>-pa Directories</c> and <c>-pz Directories</c>. These add + <c>Directories</c> to the head or the end of the code path, + respectively. Example:</p> <pre> % <input>erl -pa /home/arne/mycode</input></pre> <p>The code server module <c>code</c> contains a number of - functions for modifying and checking the search path, see - <c>code(3)</c>.</p> + functions for modifying and checking the search path, see the + <c>code(3)</c> manual page in Kernel.</p> </section> <section> @@ -192,49 +196,65 @@ init:stop()</pre> <cell align="left" valign="middle"><em>Documented in</em></cell> </row> <row> - <cell align="left" valign="middle">module</cell> + <cell align="left" valign="middle">Module</cell> <cell align="left" valign="middle"><c>.erl</c></cell> - <cell align="left" valign="middle">Erlang Reference Manual</cell> + <cell align="left" valign="middle"> + <seealso marker="erlang ref manual"> + Erlang Reference Manual</seealso></cell> </row> <row> - <cell align="left" valign="middle">include file</cell> + <cell align="left" valign="middle">Include file</cell> <cell align="left" valign="middle"><c>.hrl</c></cell> - <cell align="left" valign="middle">Erlang Reference Manual</cell> + <cell align="left" valign="middle"> + <seealso marker="erlang ref manual"> + Erlang Reference Manual</seealso></cell> </row> <row> - <cell align="left" valign="middle">release resource file</cell> + <cell align="left" valign="middle">Release resource file</cell> <cell align="left" valign="middle"><c>.rel</c></cell> - <cell align="left" valign="middle"><c>rel(4)</c></cell> + <cell align="left" valign="middle"> + <seealso marker="sasl:rel">rel(4)</seealso> + manual page in SASL</cell> </row> <row> - <cell align="left" valign="middle">application resource file</cell> + <cell align="left" valign="middle">Application resource file</cell> <cell align="left" valign="middle"><c>.app</c></cell> - <cell align="left" valign="middle"><c>app(4)</c></cell> + <cell align="left" valign="middle"> + <seealso marker="kernel:app">app(4)</seealso> + manual page in Kernel</cell> </row> <row> - <cell align="left" valign="middle">boot script</cell> + <cell align="left" valign="middle">Boot script</cell> <cell align="left" valign="middle"><c>.script</c></cell> - <cell align="left" valign="middle"><c>script(4)</c></cell> + <cell align="left" valign="middle"> + <seealso marker="sasl:script">script(4)</seealso> + manual page in SASL</cell> </row> <row> - <cell align="left" valign="middle">binary boot script</cell> + <cell align="left" valign="middle">Binary boot script</cell> <cell align="left" valign="middle"><c>.boot</c></cell> <cell align="left" valign="middle">-</cell> </row> <row> - <cell align="left" valign="middle">configuration file</cell> + <cell align="left" valign="middle">Configuration file</cell> <cell align="left" valign="middle"><c>.config</c></cell> - <cell align="left" valign="middle"><c>config(4)</c></cell> + <cell align="left" valign="middle"> + <seealso marker="kernel:config">config(4)</seealso> + manual page in Kernel</cell> </row> <row> - <cell align="left" valign="middle">application upgrade file</cell> + <cell align="left" valign="middle">Application upgrade file</cell> <cell align="left" valign="middle"><c>.appup</c></cell> - <cell align="left" valign="middle"><c>appup(4)</c></cell> + <cell align="left" valign="middle"> + <seealso marker="sasl:appup">appup(4)</seealso> + manual page in SASL</cell> </row> <row> - <cell align="left" valign="middle">release upgrade file</cell> + <cell align="left" valign="middle">Release upgrade file</cell> <cell align="left" valign="middle"><c>relup</c></cell> - <cell align="left" valign="middle"><c>relup(4)</c></cell> + <cell align="left" valign="middle"> + <seealso marker="sasl:relup">relup(4)</seealso> + manual page in SASL</cell> </row> <tcaption>File Types</tcaption> </table> |