diff options
Diffstat (limited to 'man/sd_event_add_inotify.xml')
| -rw-r--r-- | man/sd_event_add_inotify.xml | 191 |
1 files changed, 191 insertions, 0 deletions
diff --git a/man/sd_event_add_inotify.xml b/man/sd_event_add_inotify.xml new file mode 100644 index 0000000..65765ea --- /dev/null +++ b/man/sd_event_add_inotify.xml @@ -0,0 +1,191 @@ +<?xml version='1.0'?> +<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" +"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> + +<!-- SPDX-License-Identifier: LGPL-2.1+ --> + +<refentry id="sd_event_add_inotify" xmlns:xi="http://www.w3.org/2001/XInclude"> + + <refentryinfo> + <title>sd_event_add_inotify</title> + <productname>systemd</productname> + </refentryinfo> + + <refmeta> + <refentrytitle>sd_event_add_inotify</refentrytitle> + <manvolnum>3</manvolnum> + </refmeta> + + <refnamediv> + <refname>sd_event_add_inotify</refname> + <refname>sd_event_source_get_inotify_mask</refname> + <refname>sd_event_inotify_handler_t</refname> + + <refpurpose>Add an "inotify" file system inode event source to an event loop</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcsynopsisinfo>#include <systemd/sd-event.h></funcsynopsisinfo> + + <funcsynopsisinfo><token>typedef</token> struct sd_event_source sd_event_source;</funcsynopsisinfo> + + <funcprototype> + <funcdef>typedef int (*<function>sd_event_inotify_handler_t</function>)</funcdef> + <paramdef>sd_event_source *<parameter>s</parameter></paramdef> + <paramdef>const struct inotify_event *<parameter>event</parameter></paramdef> + <paramdef>void *<parameter>userdata</parameter></paramdef> + </funcprototype> + + <funcprototype> + <funcdef>int <function>sd_event_add_inotify</function></funcdef> + <paramdef>sd_event *<parameter>event</parameter></paramdef> + <paramdef>sd_event_source **<parameter>source</parameter></paramdef> + <paramdef>const char *<parameter>path</parameter></paramdef> + <paramdef>uint32_t <parameter>mask</parameter></paramdef> + <paramdef>sd_event_inotify_handler_t <parameter>handler</parameter></paramdef> + <paramdef>void *<parameter>userdata</parameter></paramdef> + </funcprototype> + + <funcprototype> + <funcdef>int <function>sd_event_source_get_inotify_mask</function></funcdef> + <paramdef>sd_event_source *<parameter>source</parameter></paramdef> + <paramdef>uint32_t *<parameter>mask</parameter></paramdef> + </funcprototype> + + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Description</title> + + <para><function>sd_event_add_inotify()</function> adds a new <citerefentry + project='man-pages'><refentrytitle>inotify</refentrytitle><manvolnum>7</manvolnum></citerefentry> file system inode + event source to an event loop. The event loop object is specified in the <parameter>event</parameter> parameter, + the event source object is returned in the <parameter>source</parameter> parameter. The <parameter>path</parameter> + parameter specifies the path of the file system inode to watch. The <parameter>handler</parameter> must reference a + function to call when the inode changes. The handler function will be passed the <parameter>userdata</parameter> + pointer, which may be chosen freely by the caller. The handler also receives a pointer to a <structname>struct + inotify_event</structname> structure containing information about the inode event. The <parameter>mask</parameter> + parameter specifie which types of inode events to watch specifically. It must contain an OR-ed combination of + <constant>IN_ACCESS</constant>, <constant>IN_ATTRIB</constant>, <constant>IN_CLOSE_WRITE</constant>, … flags. See + <citerefentry project='man-pages'><refentrytitle>inotify</refentrytitle><manvolnum>7</manvolnum></citerefentry> for + further information.</para> + + <para>If multiple event sources are installed for the same inode the backing inotify watch descriptor is + automatically shared. The mask parameter may contain any flag defined by the inotify API, with the exception of + <constant>IN_MASK_ADD</constant>.</para> + + <para>The handler is enabled continuously (<constant>SD_EVENT_ON</constant>), but this may be changed with + <citerefentry><refentrytitle>sd_event_source_set_enabled</refentrytitle><manvolnum>3</manvolnum></citerefentry>. Alternatively, + the <constant>IN_ONESHOT</constant> mask flag may be used to request <constant>SD_EVENT_ONESHOT</constant> mode. + If the handler function returns a negative error code, it will be disabled after the invocation, even if the + <constant>SD_EVENT_ON</constant> mode was requested before. + </para> + + <para>As a special limitation the priority of inotify event sources may only be altered (see + <citerefentry><refentrytitle>sd_event_source_set_priority</refentrytitle><manvolnum>3</manvolnum></citerefentry>) + in the time between creation of the event source object with <function>sd_event_add_inotify()</function> and the + beginning of the next event loop iteration. Attempts of changing the priority any later will be refused. Consider + freeing and allocating a new inotify event source to change the priority at that point.</para> + + <para>To destroy an event source object use + <citerefentry><refentrytitle>sd_event_source_unref</refentrytitle><manvolnum>3</manvolnum></citerefentry>, but note + that the event source is only removed from the event loop when all references to the event source are dropped. To + make sure an event source does not fire anymore, even when there's still a reference to it kept, consider disabling + it with + <citerefentry><refentrytitle>sd_event_source_set_enabled</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para> + + <para>If the second parameter of <function>sd_event_add_inotify()</function> is passed as NULL no reference to the + event source object is returned. In this case the event source is considered "floating", and will be destroyed + implicitly when the event loop itself is destroyed.</para> + + <para><function>sd_event_source_get_inotify_mask()</function> retrieves the configured inotify watch mask of an + event source created previously with <function>sd_event_add_inotify()</function>. It takes the event source object + as the <parameter>source</parameter> parameter and a pointer to a <type>uint32_t</type> variable to return the mask + in.</para> + </refsect1> + + <refsect1> + <title>Return Value</title> + + <para>On success, these functions return 0 or a positive integer. On failure, they return a negative errno-style + error code.</para> + </refsect1> + + <refsect1> + <title>Errors</title> + + <para>Returned errors may indicate the following problems:</para> + + <variablelist> + <varlistentry> + <term><constant>-ENOMEM</constant></term> + + <listitem><para>Not enough memory to allocate an object.</para></listitem> + </varlistentry> + + <varlistentry> + <term><constant>-EINVAL</constant></term> + + <listitem><para>An invalid argument has been passed. This includes specifying a mask with + <constant>IN_MASK_ADD</constant> set.</para></listitem> + </varlistentry> + + <varlistentry> + <term><constant>-ESTALE</constant></term> + + <listitem><para>The event loop is already terminated.</para></listitem> + + </varlistentry> + + <varlistentry> + <term><constant>-ECHILD</constant></term> + + <listitem><para>The event loop has been created in a different process.</para></listitem> + + </varlistentry> + + <varlistentry> + <term><constant>-EDOM</constant></term> + + <listitem><para>The passed event source is not an inotify process event source.</para></listitem> + </varlistentry> + + </variablelist> + </refsect1> + + <refsect1> + <title>Examples</title> + + <example> + <title>A simple program that uses inotify to monitor one or two directories</title> + + <programlisting><xi:include href="inotify-watch-tmp.c" parse="text" /></programlisting> + </example> + </refsect1> + + <xi:include href="libsystemd-pkgconfig.xml" /> + + <refsect1> + <title>See Also</title> + + <para> + <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, + <citerefentry><refentrytitle>sd-event</refentrytitle><manvolnum>3</manvolnum></citerefentry>, + <citerefentry><refentrytitle>sd_event_new</refentrytitle><manvolnum>3</manvolnum></citerefentry>, + <citerefentry><refentrytitle>sd_event_now</refentrytitle><manvolnum>3</manvolnum></citerefentry>, + <citerefentry><refentrytitle>sd_event_add_io</refentrytitle><manvolnum>3</manvolnum></citerefentry>, + <citerefentry><refentrytitle>sd_event_add_time</refentrytitle><manvolnum>3</manvolnum></citerefentry>, + <citerefentry><refentrytitle>sd_event_add_signal</refentrytitle><manvolnum>3</manvolnum></citerefentry>, + <citerefentry><refentrytitle>sd_event_add_defer</refentrytitle><manvolnum>3</manvolnum></citerefentry>, + <citerefentry><refentrytitle>sd_event_add_child</refentrytitle><manvolnum>3</manvolnum></citerefentry>, + <citerefentry><refentrytitle>sd_event_source_set_enabled</refentrytitle><manvolnum>3</manvolnum></citerefentry>, + <citerefentry><refentrytitle>sd_event_source_set_priority</refentrytitle><manvolnum>3</manvolnum></citerefentry>, + <citerefentry><refentrytitle>sd_event_source_set_userdata</refentrytitle><manvolnum>3</manvolnum></citerefentry>, + <citerefentry><refentrytitle>sd_event_source_set_description</refentrytitle><manvolnum>3</manvolnum></citerefentry>, + <citerefentry project='man-pages'><refentrytitle>waitid</refentrytitle><manvolnum>2</manvolnum></citerefentry> + </para> + </refsect1> + +</refentry> |