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| <h4 class="subsection">18.2.4 setlogmask</h4> |
| |
| <p>The symbols referred to in this section are declared in the file |
| <samp><span class="file">syslog.h</span></samp>. |
| |
| <!-- syslog.h --> |
| <!-- BSD --> |
| <div class="defun"> |
| — Function: int <b>setlogmask</b> (<var>int mask</var>)<var><a name="index-setlogmask-2065"></a></var><br> |
| <blockquote> |
| <p><code>setlogmask</code> sets a mask (the “logmask”) that determines which |
| future <code>syslog</code> calls shall be ignored. If a program has not |
| called <code>setlogmask</code>, <code>syslog</code> doesn't ignore any calls. You |
| can use <code>setlogmask</code> to specify that messages of particular |
| priorities shall be ignored in the future. |
| |
| <p>A <code>setlogmask</code> call overrides any previous <code>setlogmask</code> call. |
| |
| <p>Note that the logmask exists entirely independently of opening and |
| closing of Syslog connections. |
| |
| <p>Setting the logmask has a similar effect to, but is not the same as, |
| configuring Syslog. The Syslog configuration may cause Syslog to |
| discard certain messages it receives, but the logmask causes certain |
| messages never to get submitted to Syslog in the first place. |
| |
| <p><var>mask</var> is a bit string with one bit corresponding to each of the |
| possible message priorities. If the bit is on, <code>syslog</code> handles |
| messages of that priority normally. If it is off, <code>syslog</code> |
| discards messages of that priority. Use the message priority macros |
| described in <a href="syslog_003b-vsyslog.html#syslog_003b-vsyslog">syslog; vsyslog</a> and the <code>LOG_MASK</code> to construct |
| an appropriate <var>mask</var> value, as in this example: |
| |
| <pre class="smallexample"> LOG_MASK(LOG_EMERG) | LOG_MASK(LOG_ERROR) |
| </pre> |
| <p>or |
| |
| <pre class="smallexample"> ~(LOG_MASK(LOG_INFO)) |
| </pre> |
| <p>There is also a <code>LOG_UPTO</code> macro, which generates a mask with the bits |
| on for a certain priority and all priorities above it: |
| |
| <pre class="smallexample"> LOG_UPTO(LOG_ERROR) |
| </pre> |
| <p>The unfortunate naming of the macro is due to the fact that internally, |
| higher numbers are used for lower message priorities. |
| |
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