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<img alt="Erlang logo" src="../../../../doc/erlang-logo.png"><br><small><a href="index.html">Reference Manual</a><br><a href="release_notes.html">Release Notes</a><br><a href="../pdf/kernel-2.15.3.pdf">PDF</a><br><a href="../../../../doc/index.html">Top</a></small><p><strong>Kernel</strong><br><strong>Reference Manual</strong><br><small>Version 2.15.3</small></p>
<br><a href="javascript:openAllFlips()">Expand All</a><br><a href="javascript:closeAllFlips()">Contract All</a><p><small><strong>Table of Contents</strong></small></p>
<ul class="flipMenu">
<li title="kernel (App)"><a href="kernel_app.html">kernel (App)
</a></li>
<li id="no" title="application " expanded="false">application<ul>
<li><a href="application.html">
Top of manual page
</a></li>
<li title="get_all_env-0"><a href="application.html#get_all_env-0">get_all_env/0</a></li>
<li title="get_all_env-1"><a href="application.html#get_all_env-1">get_all_env/1</a></li>
<li title="get_all_key-0"><a href="application.html#get_all_key-0">get_all_key/0</a></li>
<li title="get_all_key-1"><a href="application.html#get_all_key-1">get_all_key/1</a></li>
<li title="get_application-0"><a href="application.html#get_application-0">get_application/0</a></li>
<li title="get_application-1"><a href="application.html#get_application-1">get_application/1</a></li>
<li title="get_env-1"><a href="application.html#get_env-1">get_env/1</a></li>
<li title="get_env-2"><a href="application.html#get_env-2">get_env/2</a></li>
<li title="get_key-1"><a href="application.html#get_key-1">get_key/1</a></li>
<li title="get_key-2"><a href="application.html#get_key-2">get_key/2</a></li>
<li title="load-1"><a href="application.html#load-1">load/1</a></li>
<li title="load-2"><a href="application.html#load-2">load/2</a></li>
<li title="loaded_applications-0"><a href="application.html#loaded_applications-0">loaded_applications/0</a></li>
<li title="permit-2"><a href="application.html#permit-2">permit/2</a></li>
<li title="set_env-3"><a href="application.html#set_env-3">set_env/3</a></li>
<li title="set_env-4"><a href="application.html#set_env-4">set_env/4</a></li>
<li title="start-1"><a href="application.html#start-1">start/1</a></li>
<li title="start-2"><a href="application.html#start-2">start/2</a></li>
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<li title="takeover-2"><a href="application.html#takeover-2">takeover/2</a></li>
<li title="unload-1"><a href="application.html#unload-1">unload/1</a></li>
<li title="unset_env-2"><a href="application.html#unset_env-2">unset_env/2</a></li>
<li title="unset_env-3"><a href="application.html#unset_env-3">unset_env/3</a></li>
<li title="which_applications-0"><a href="application.html#which_applications-0">which_applications/0</a></li>
<li title="which_applications-1"><a href="application.html#which_applications-1">which_applications/1</a></li>
<li title="Module:start-2"><a href="application.html#Module:start-2">Module:start/2</a></li>
<li title="Module:start_phase-3"><a href="application.html#Module:start_phase-3">Module:start_phase/3</a></li>
<li title="Module:prep_stop-1"><a href="application.html#Module:prep_stop-1">Module:prep_stop/1</a></li>
<li title="Module:stop-1"><a href="application.html#Module:stop-1">Module:stop/1</a></li>
<li title="Module:config_change-3"><a href="application.html#Module:config_change-3">Module:config_change/3</a></li>
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<li title="cookie-1"><a href="auth.html#cookie-1">cookie/1</a></li>
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<li id="no" title="code " expanded="false">code<ul>
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<li title="set_path-1"><a href="code.html#set_path-1">set_path/1</a></li>
<li title="get_path-0"><a href="code.html#get_path-0">get_path/0</a></li>
<li title="add_path-1"><a href="code.html#add_path-1">add_path/1</a></li>
<li title="add_pathz-1"><a href="code.html#add_pathz-1">add_pathz/1</a></li>
<li title="add_patha-1"><a href="code.html#add_patha-1">add_patha/1</a></li>
<li title="add_paths-1"><a href="code.html#add_paths-1">add_paths/1</a></li>
<li title="add_pathsz-1"><a href="code.html#add_pathsz-1">add_pathsz/1</a></li>
<li title="add_pathsa-1"><a href="code.html#add_pathsa-1">add_pathsa/1</a></li>
<li title="del_path-1"><a href="code.html#del_path-1">del_path/1</a></li>
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<li title="load_abs-1"><a href="code.html#load_abs-1">load_abs/1</a></li>
<li title="ensure_loaded-1"><a href="code.html#ensure_loaded-1">ensure_loaded/1</a></li>
<li title="load_binary-3"><a href="code.html#load_binary-3">load_binary/3</a></li>
<li title="delete-1"><a href="code.html#delete-1">delete/1</a></li>
<li title="purge-1"><a href="code.html#purge-1">purge/1</a></li>
<li title="soft_purge-1"><a href="code.html#soft_purge-1">soft_purge/1</a></li>
<li title="is_loaded-1"><a href="code.html#is_loaded-1">is_loaded/1</a></li>
<li title="all_loaded-0"><a href="code.html#all_loaded-0">all_loaded/0</a></li>
<li title="which-1"><a href="code.html#which-1">which/1</a></li>
<li title="get_object_code-1"><a href="code.html#get_object_code-1">get_object_code/1</a></li>
<li title="root_dir-0"><a href="code.html#root_dir-0">root_dir/0</a></li>
<li title="lib_dir-0"><a href="code.html#lib_dir-0">lib_dir/0</a></li>
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<li title="priv_dir-1"><a href="code.html#priv_dir-1">priv_dir/1</a></li>
<li title="objfile_extension-0"><a href="code.html#objfile_extension-0">objfile_extension/0</a></li>
<li title="stick_dir-1"><a href="code.html#stick_dir-1">stick_dir/1</a></li>
<li title="unstick_dir-1"><a href="code.html#unstick_dir-1">unstick_dir/1</a></li>
<li title="is_sticky-1"><a href="code.html#is_sticky-1">is_sticky/1</a></li>
<li title="rehash-0"><a href="code.html#rehash-0">rehash/0</a></li>
<li title="where_is_file-1"><a href="code.html#where_is_file-1">where_is_file/1</a></li>
<li title="clash-0"><a href="code.html#clash-0">clash/0</a></li>
<li title="is_module_native-1"><a href="code.html#is_module_native-1">is_module_native/1</a></li>
</ul>
</li>
<li id="no" title="disk_log " expanded="false">disk_log<ul>
<li><a href="disk_log.html">
Top of manual page
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<li title="accessible_logs-0"><a href="disk_log.html#accessible_logs-0">accessible_logs/0</a></li>
<li title="alog-2"><a href="disk_log.html#alog-2">alog/2</a></li>
<li title="balog-2"><a href="disk_log.html#balog-2">balog/2</a></li>
<li title="alog_terms-2"><a href="disk_log.html#alog_terms-2">alog_terms/2</a></li>
<li title="balog_terms-2"><a href="disk_log.html#balog_terms-2">balog_terms/2</a></li>
<li title="block-1"><a href="disk_log.html#block-1">block/1</a></li>
<li title="block-2"><a href="disk_log.html#block-2">block/2</a></li>
<li title="change_header-2"><a href="disk_log.html#change_header-2">change_header/2</a></li>
<li title="change_notify-3"><a href="disk_log.html#change_notify-3">change_notify/3</a></li>
<li title="change_size-2"><a href="disk_log.html#change_size-2">change_size/2</a></li>
<li title="chunk-2"><a href="disk_log.html#chunk-2">chunk/2</a></li>
<li title="chunk-3"><a href="disk_log.html#chunk-3">chunk/3</a></li>
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<li title="bchunk-3"><a href="disk_log.html#bchunk-3">bchunk/3</a></li>
<li title="chunk_info-1"><a href="disk_log.html#chunk_info-1">chunk_info/1</a></li>
<li title="chunk_step-3"><a href="disk_log.html#chunk_step-3">chunk_step/3</a></li>
<li title="close-1"><a href="disk_log.html#close-1">close/1</a></li>
<li title="format_error-1"><a href="disk_log.html#format_error-1">format_error/1</a></li>
<li title="inc_wrap_file-1"><a href="disk_log.html#inc_wrap_file-1">inc_wrap_file/1</a></li>
<li title="info-1"><a href="disk_log.html#info-1">info/1</a></li>
<li title="lclose-1"><a href="disk_log.html#lclose-1">lclose/1</a></li>
<li title="lclose-2"><a href="disk_log.html#lclose-2">lclose/2</a></li>
<li title="log-2"><a href="disk_log.html#log-2">log/2</a></li>
<li title="blog-2"><a href="disk_log.html#blog-2">blog/2</a></li>
<li title="log_terms-2"><a href="disk_log.html#log_terms-2">log_terms/2</a></li>
<li title="blog_terms-2"><a href="disk_log.html#blog_terms-2">blog_terms/2</a></li>
<li title="open-1"><a href="disk_log.html#open-1">open/1</a></li>
<li title="pid2name-1"><a href="disk_log.html#pid2name-1">pid2name/1</a></li>
<li title="reopen-2"><a href="disk_log.html#reopen-2">reopen/2</a></li>
<li title="reopen-3"><a href="disk_log.html#reopen-3">reopen/3</a></li>
<li title="breopen-3"><a href="disk_log.html#breopen-3">breopen/3</a></li>
<li title="sync-1"><a href="disk_log.html#sync-1">sync/1</a></li>
<li title="truncate-1"><a href="disk_log.html#truncate-1">truncate/1</a></li>
<li title="truncate-2"><a href="disk_log.html#truncate-2">truncate/2</a></li>
<li title="btruncate-2"><a href="disk_log.html#btruncate-2">btruncate/2</a></li>
<li title="unblock-1"><a href="disk_log.html#unblock-1">unblock/1</a></li>
</ul>
</li>
<li id="no" title="erl_boot_server " expanded="false">erl_boot_server<ul>
<li><a href="erl_boot_server.html">
Top of manual page
</a></li>
<li title="start-1"><a href="erl_boot_server.html#start-1">start/1</a></li>
<li title="start_link-1"><a href="erl_boot_server.html#start_link-1">start_link/1</a></li>
<li title="add_slave-1"><a href="erl_boot_server.html#add_slave-1">add_slave/1</a></li>
<li title="delete_slave-1"><a href="erl_boot_server.html#delete_slave-1">delete_slave/1</a></li>
<li title="which_slaves-0"><a href="erl_boot_server.html#which_slaves-0">which_slaves/0</a></li>
</ul>
</li>
<li id="no" title="erl_ddll " expanded="false">erl_ddll<ul>
<li><a href="erl_ddll.html">
Top of manual page
</a></li>
<li title="demonitor-1"><a href="erl_ddll.html#demonitor-1">demonitor/1</a></li>
<li title="info-0"><a href="erl_ddll.html#info-0">info/0</a></li>
<li title="info-1"><a href="erl_ddll.html#info-1">info/1</a></li>
<li title="info-2"><a href="erl_ddll.html#info-2">info/2</a></li>
<li title="load-2"><a href="erl_ddll.html#load-2">load/2</a></li>
<li title="load_driver-2"><a href="erl_ddll.html#load_driver-2">load_driver/2</a></li>
<li title="monitor-2"><a href="erl_ddll.html#monitor-2">monitor/2</a></li>
<li title="reload-2"><a href="erl_ddll.html#reload-2">reload/2</a></li>
<li title="reload_driver-2"><a href="erl_ddll.html#reload_driver-2">reload_driver/2</a></li>
<li title="try_load-3"><a href="erl_ddll.html#try_load-3">try_load/3</a></li>
<li title="try_unload-2"><a href="erl_ddll.html#try_unload-2">try_unload/2</a></li>
<li title="unload-1"><a href="erl_ddll.html#unload-1">unload/1</a></li>
<li title="unload_driver-1"><a href="erl_ddll.html#unload_driver-1">unload_driver/1</a></li>
<li title="loaded_drivers-0"><a href="erl_ddll.html#loaded_drivers-0">loaded_drivers/0</a></li>
<li title="format_error-1"><a href="erl_ddll.html#format_error-1">format_error/1</a></li>
</ul>
</li>
<li title="erl_prim_loader"><a href="erl_prim_loader.html">erl_prim_loader</a></li>
<li title="erlang"><a href="erlang.html">erlang</a></li>
<li id="no" title="error_handler " expanded="false">error_handler<ul>
<li><a href="error_handler.html">
Top of manual page
</a></li>
<li title="undefined_function-3"><a href="error_handler.html#undefined_function-3">undefined_function/3</a></li>
<li title="undefined_lambda-3"><a href="error_handler.html#undefined_lambda-3">undefined_lambda/3</a></li>
</ul>
</li>
<li id="no" title="error_logger " expanded="false">error_logger<ul>
<li><a href="error_logger.html">
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</a></li>
<li title="error_msg-1"><a href="error_logger.html#error_msg-1">error_msg/1</a></li>
<li title="error_msg-2"><a href="error_logger.html#error_msg-2">error_msg/2</a></li>
<li title="format-2"><a href="error_logger.html#format-2">format/2</a></li>
<li title="error_report-1"><a href="error_logger.html#error_report-1">error_report/1</a></li>
<li title="error_report-2"><a href="error_logger.html#error_report-2">error_report/2</a></li>
<li title="warning_map-0"><a href="error_logger.html#warning_map-0">warning_map/0</a></li>
<li title="warning_msg-1"><a href="error_logger.html#warning_msg-1">warning_msg/1</a></li>
<li title="warning_msg-2"><a href="error_logger.html#warning_msg-2">warning_msg/2</a></li>
<li title="warning_report-1"><a href="error_logger.html#warning_report-1">warning_report/1</a></li>
<li title="warning_report-2"><a href="error_logger.html#warning_report-2">warning_report/2</a></li>
<li title="info_msg-1"><a href="error_logger.html#info_msg-1">info_msg/1</a></li>
<li title="info_msg-2"><a href="error_logger.html#info_msg-2">info_msg/2</a></li>
<li title="info_report-1"><a href="error_logger.html#info_report-1">info_report/1</a></li>
<li title="info_report-2"><a href="error_logger.html#info_report-2">info_report/2</a></li>
<li title="add_report_handler-1"><a href="error_logger.html#add_report_handler-1">add_report_handler/1</a></li>
<li title="add_report_handler-2"><a href="error_logger.html#add_report_handler-2">add_report_handler/2</a></li>
<li title="delete_report_handler-1"><a href="error_logger.html#delete_report_handler-1">delete_report_handler/1</a></li>
<li title="tty-1"><a href="error_logger.html#tty-1">tty/1</a></li>
<li title="logfile-1"><a href="error_logger.html#logfile-1">logfile/1</a></li>
</ul>
</li>
<li id="no" title="file " expanded="false">file<ul>
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<li title="change_owner-2"><a href="file.html#change_owner-2">change_owner/2</a></li>
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<li title="change_time-2"><a href="file.html#change_time-2">change_time/2</a></li>
<li title="change_time-3"><a href="file.html#change_time-3">change_time/3</a></li>
<li title="close-1"><a href="file.html#close-1">close/1</a></li>
<li title="consult-1"><a href="file.html#consult-1">consult/1</a></li>
<li title="copy-2"><a href="file.html#copy-2">copy/2</a></li>
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<li title="delete-1"><a href="file.html#delete-1">delete/1</a></li>
<li title="eval-1"><a href="file.html#eval-1">eval/1</a></li>
<li title="eval-2"><a href="file.html#eval-2">eval/2</a></li>
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<li title="connect-3"><a href="gen_tcp.html#connect-3">connect/3</a></li>
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<li title="close-1"><a href="gen_tcp.html#close-1">close/1</a></li>
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<li title="send-4"><a href="gen_udp.html#send-4">send/4</a></li>
<li title="recv-2"><a href="gen_udp.html#recv-2">recv/2</a></li>
<li title="recv-3"><a href="gen_udp.html#recv-3">recv/3</a></li>
<li title="controlling_process-2"><a href="gen_udp.html#controlling_process-2">controlling_process/2</a></li>
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<li title="abort-2"><a href="gen_sctp.html#abort-2">abort/2</a></li>
<li title="close-1"><a href="gen_sctp.html#close-1">close/1</a></li>
<li title="connect-4"><a href="gen_sctp.html#connect-4">connect/4</a></li>
<li title="connect-5"><a href="gen_sctp.html#connect-5">connect/5</a></li>
<li title="connect_init-4"><a href="gen_sctp.html#connect_init-4">connect_init/4</a></li>
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<li title="eof-2"><a href="gen_sctp.html#eof-2">eof/2</a></li>
<li title="listen-2"><a href="gen_sctp.html#listen-2">listen/2</a></li>
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<li title="open-1"><a href="gen_sctp.html#open-1">open/1</a></li>
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<li title="recv-1"><a href="gen_sctp.html#recv-1">recv/1</a></li>
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<li title="safe_multi_server_call-3"><a href="rpc.html#safe_multi_server_call-3">safe_multi_server_call/3</a></li>
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<div id="content">
<div class="innertube">
<!-- refpage --><center><h1>os</h1></center>
<h3>MODULE</h3>
<div class="REFBODY">os</div>
<h3>MODULE SUMMARY</h3>
<div class="REFBODY">Operating System Specific Functions</div>
<h3>DESCRIPTION</h3>
<div class="REFBODY"><p>
<p>The functions in this module are operating system specific.
Careless use of these functions will result in programs that will
only run on a specific platform. On the other hand, with careful
use these functions can be of help in enabling a program to run on
most platforms.</p>
</p></div>
<h3>EXPORTS</h3>
<p><a name="cmd-1"></a><span class="bold_code">cmd(Command) -> string()</span><br><div class="REFBODY">
<p>Types:</p>
<div class="REFTYPES"><span class="bold_code">Command = atom() | <span class="bold_code"><a href="javascript:erlhref('../../../../doc/../','stdlib','io_lib.html#type-chars');">io_lib:chars()</a></span></span></div>
</div></p>
<div class="REFBODY"><p>
<p>Executes <span class="code">Command</span> in a command shell of the target OS,
captures the standard output of the command and returns this
result as a string. This function is a replacement of
the previous <span class="code">unix:cmd/1</span>; on a Unix platform they are
equivalent.</p>
<p>Examples:</p>
<div class="example"><pre>
LsOut = os:cmd("ls"), % on unix platform
DirOut = os:cmd("dir"), % on Win32 platform</pre></div>
<p>Note that in some cases, standard output of a command when
called from another program (for example, <span class="code">os:cmd/1</span>)
may differ, compared to the standard output of the command
when called directly from an OS command shell.</p>
</p></div>
<p><a name="find_executable-1"></a><span class="bold_code">find_executable(Name) -> Filename | false</span><br><a name="find_executable-2"></a><span class="bold_code">find_executable(Name, Path) -> Filename | false</span><br><div class="REFBODY">
<p>Types:</p>
<div class="REFTYPES"><span class="bold_code">Name = Path = Filename = string()</span></div>
<div class="REFTYPES"><span class="bold_code"></span></div>
<div class="REFTYPES"><span class="bold_code"></span></div>
</div></p>
<div class="REFBODY"><p>
<p>These two functions look up an executable program given its
name and a search path, in the same way as the underlying
operating system. <span class="code">find_executable/1</span> uses the current
execution path (that is, the environment variable PATH on
Unix and Windows).</p>
<p><span class="code">Path</span>, if given, should conform to the syntax of
execution paths on the operating system. The absolute
filename of the executable program <span class="code">Name</span> is returned,
or <span class="code">false</span> if the program was not found.</p>
</p></div>
<p><a name="getenv-0"><span class="bold_code">getenv() -> [string()]</span></a><br></p>
<div class="REFBODY"><p>
<p>Returns a list of all environment variables.
Each environment variable is given as a single string on
the format <span class="code">"VarName=Value"</span>, where <span class="code">VarName</span> is
the name of the variable and <span class="code">Value</span> its value.</p>
<p>If Unicode file name encoding is in effect (see the <span class="bold_code"><a href="javascript:erlhref('../../../../doc/../','erts','erl.html#file_name_encoding');">erl manual
page</a></span>), the strings may contain characters with
codepoints > 255.</p>
</p></div>
<p><a name="getenv-1"><span class="bold_code">getenv(VarName) -> Value | false</span></a><br></p>
<div class="REFBODY">
<p>Types:</p>
<div class="REFTYPES">
<span class="bold_code">VarName = string() </span><br>
</div>
<div class="REFTYPES">
<span class="bold_code">Value = string()</span><br>
</div>
</div>
<div class="REFBODY"><p>
<p>Returns the <span class="code">Value</span> of the environment variable
<span class="code">VarName</span>, or <span class="code">false</span> if the environment variable
is undefined.</p>
<p>If Unicode file name encoding is in effect (see the <span class="bold_code"><a href="javascript:erlhref('../../../../doc/../','erts','erl.html#file_name_encoding');">erl manual
page</a></span>), the strings (both <span class="code">VarName</span> and
<span class="code">Value</span>) may contain characters with codepoints > 255.</p>
</p></div>
<p><a name="getpid-0"><span class="bold_code">getpid() -> Value </span></a><br></p>
<div class="REFBODY">
<p>Types:</p>
<div class="REFTYPES">
<span class="bold_code">Value = string()</span><br>
</div>
</div>
<div class="REFBODY"><p>
<p>Returns the process identifier of the current Erlang emulator
in the format most commonly used by the operating system
environment. <span class="code">Value</span> is returned as a string containing
the (usually) numerical identifier for a process. On Unix,
this is typically the return value of the <span class="code">getpid()</span>
system call. On VxWorks, <span class="code">Value</span> contains the task id
(decimal notation) of the Erlang task. On Windows,
the process id as returned by the <span class="code">GetCurrentProcessId()</span>
system call is used.</p>
</p></div>
<p><a name="putenv-2"><span class="bold_code">putenv(VarName, Value) -> true</span></a><br></p>
<div class="REFBODY">
<p>Types:</p>
<div class="REFTYPES">
<span class="bold_code">VarName = string() </span><br>
</div>
<div class="REFTYPES">
<span class="bold_code">Value = string()</span><br>
</div>
</div>
<div class="REFBODY"><p>
<p>Sets a new <span class="code">Value</span> for the environment variable
<span class="code">VarName</span>.</p>
<p>If Unicode filename encoding is in effect (see the <span class="bold_code"><a href="javascript:erlhref('../../../../doc/../','erts','erl.html#file_name_encoding');">erl manual
page</a></span>), the strings (both <span class="code">VarName</span> and
<span class="code">Value</span>) may contain characters with codepoints > 255.</p>
<p>On Unix platforms, the environment will be set using UTF-8 encoding
if Unicode file name translation is in effect. On Windows the
environment is set using wide character interfaces.</p>
</p></div>
<p><a name="timestamp-0"><span class="bold_code">timestamp() -> Timestamp</span></a><br></p>
<div class="REFBODY">
<p>Types:</p>
<div class="REFTYPES">
<span class="bold_code">Timestamp = {MegaSecs, Secs, MicroSecs} = <span class="bold_code"><a href="javascript:erlhref('../../../../doc/../','erts','erlang.html#type-timestamp');">erlang:timestamp()</a></span></span><br>
</div>
<div class="REFTYPES">
<span class="bold_code">MegaSecs = Secs = MicroSecs = integer() >= 0</span><br>
</div>
</div>
<div class="REFBODY"><p>
<p>Returns a tuple in the same format as <span class="bold_code"><a href="javascript:erlhref('../../../../doc/../','erts','erlang.html#now-0');">erlang:now/0</a></span>. The difference is that this function returns what the operating system thinks (a.k.a. the wall clock time) without any attempts at time correction. The result of two different calls to this function is <strong>not</strong> guaranteed to be different.</p>
<p>The most obvious use for this function is logging. The tuple can be used together with the function <span class="bold_code"><a href="javascript:erlhref('../../../../doc/../','stdlib','calendar.html#now_to_universal_time-1');">calendar:now_to_universal_time/1</a></span>
or <span class="bold_code"><a href="javascript:erlhref('../../../../doc/../','stdlib','calendar.html#now_to_local_time-1');">calendar:now_to_local_time/1</a></span> to get calendar time. Using the calendar time together with the <span class="code">MicroSecs</span> part of the return tuple from this function allows you to log timestamps in high resolution and consistent with the time in the rest of the operating system.</p>
<p>Example of code formatting a string in the format "DD Mon YYYY HH:MM:SS.mmmmmm", where DD is the day of month, Mon is the textual month name, YYYY is the year, HH:MM:SS is the time and mmmmmm is the microseconds in six positions:</p>
<div class="example"><pre>
-module(print_time).
-export([format_utc_timestamp/0]).
format_utc_timestamp() ->
TS = {_,_,Micro} = os:timestamp(),
{{Year,Month,Day},{Hour,Minute,Second}} =
calendar:now_to_universal_time(TS),
Mstr = element(Month,{"Jan","Feb","Mar","Apr","May","Jun","Jul",
"Aug","Sep","Oct","Nov","Dec"}),
io_lib:format("~2w ~s ~4w ~2w:~2..0w:~2..0w.~6..0w",
[Day,Mstr,Year,Hour,Minute,Second,Micro]).
</pre></div>
<p>The module above could be used in the following way:</p>
<div class="example"><pre>
1> <span class="bold_code">io:format("~s~n",[print_time:format_utc_timestamp()]).</span>
29 Apr 2009 9:55:30.051711
</pre></div>
</p></div>
<p><a name="type-0"></a><span class="bold_code">type() -> vxworks | {Osfamily, Osname}</span><br><div class="REFBODY">
<p>Types:</p>
<div class="REFTYPES"><span class="bold_code">Osfamily = unix | win32</span></div>
<div class="REFTYPES"><span class="bold_code">Osname = atom()</span></div>
</div></p>
<div class="REFBODY"><p>
<p>Returns the <span class="code">Osfamily</span> and, in some cases, <span class="code">Osname</span>
of the current operating system.</p>
<p>On Unix, <span class="code">Osname</span> will have same value as
<span class="code">uname -s</span> returns, but in lower case. For example, on
Solaris 1 and 2, it will be <span class="code">sunos</span>.</p>
<p>In Windows, <span class="code">Osname</span> will be either <span class="code">nt</span> (on
Windows NT), or <span class="code">windows</span> (on Windows 95).</p>
<p>On VxWorks the OS family alone is returned, that is
<span class="code">vxworks</span>.</p>
<div class="note">
<div class="label">Note</div>
<div class="content"><p>
<p>Think twice before using this function. Use the
<span class="code">filename</span> module if you want to inspect or build
file names in a portable way.
Avoid matching on the <span class="code">Osname</span> atom.</p>
</p></div>
</div>
</p></div>
<p><a name="version-0"></a><span class="bold_code">version() -> VersionString | {Major, Minor, Release}</span><br><div class="REFBODY">
<p>Types:</p>
<div class="REFTYPES"><span class="bold_code">VersionString = string()</span></div>
<div class="REFTYPES"><span class="bold_code">Major = Minor = Release = integer() >= 0</span></div>
<div class="REFTYPES"><span class="bold_code"></span></div>
<div class="REFTYPES"><span class="bold_code"></span></div>
</div></p>
<div class="REFBODY"><p>
<p>Returns the operating system version.
On most systems, this function returns a tuple, but a string
will be returned instead if the system has versions which
cannot be expressed as three numbers.</p>
<div class="note">
<div class="label">Note</div>
<div class="content"><p>
<p>Think twice before using this function. If you still need
to use it, always <span class="code">call os:type()</span> first.</p>
</p></div>
</div>
</p></div>
</div>
<div class="footer">
<hr>
<p>Copyright © 1997-2012 Ericsson AB. All Rights Reserved.</p>
</div>
</div>
</div></body>
</html>
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Fedora
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i386
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files
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931
