- <structname>e->name</structname> to an errno-like value
- using the same rules as <function>sd_bus_error_set</function>.
- </para>
+ <structname>e->name</structname> to an errno-like value using the
+ same rules as <function>sd_bus_error_set</function>. If
+ <parameter>e</parameter> is <constant>NULL</constant>, 0 will be
+ returned.</para>