diff --git a/reference/random/functions/mt-srand.xml b/reference/random/functions/mt-srand.xml
index dead65437188..08b76123de15 100644
--- a/reference/random/functions/mt-srand.xml
+++ b/reference/random/functions/mt-srand.xml
@@ -9,7 +9,7 @@
   &reftitle.description;
   <methodsynopsis>
    <type>void</type><methodname>mt_srand</methodname>
-   <methodparam choice="opt"><type>int</type><parameter>seed</parameter><initializer>0</initializer></methodparam>
+   <methodparam choice="opt"><type class="union"><type>int</type><type>null</type></type><parameter>seed</parameter><initializer>&null;</initializer></methodparam>
    <methodparam choice="opt"><type>int</type><parameter>mode</parameter><initializer><constant>MT_RAND_MT19937</constant></initializer></methodparam>
   </methodsynopsis>
   <para>
@@ -30,7 +30,13 @@
      <term><parameter>seed</parameter></term>
      <listitem>
       <para>
-       An arbitrary <type>int</type> seed value.
+       Fills the state with values generated with a linear congruential generator
+       that was seeded with <parameter>seed</parameter> interpreted as an unsigned
+       32 bit integer.
+      </para>
+      <para>
+       If <parameter>seed</parameter> is omitted or &null;, a random unsigned
+       32-bit integer will be used.
       </para>
      </listitem>
     </varlistentry>
@@ -77,6 +83,12 @@
       </row>
      </thead>
      <tbody>
+      <row>
+       <entry>8.3.0</entry>
+       <entry>
+        <parameter>seed</parameter> is now nullable.
+       </entry>
+      </row>
       <row>
        <entry>7.1.0</entry>
        <entry>
diff --git a/reference/random/functions/srand.xml b/reference/random/functions/srand.xml
index 4585e07ef0d9..fe088e909c53 100644
--- a/reference/random/functions/srand.xml
+++ b/reference/random/functions/srand.xml
@@ -9,7 +9,7 @@
   &reftitle.description;
    <methodsynopsis>
    <type>void</type><methodname>srand</methodname>
-   <methodparam choice="opt"><type>int</type><parameter>seed</parameter><initializer>0</initializer></methodparam>
+   <methodparam choice="opt"><type class="union"><type>int</type><type>null</type></type><parameter>seed</parameter><initializer>&null;</initializer></methodparam>
    <methodparam choice="opt"><type>int</type><parameter>mode</parameter><initializer><constant>MT_RAND_MT19937</constant></initializer></methodparam>
   </methodsynopsis>
   <para>
@@ -31,7 +31,13 @@
      <term><parameter>seed</parameter></term>
      <listitem>
       <para>
-       An arbitrary <type>int</type> seed value.
+       Fills the state with values generated with a linear congruential generator
+       that was seeded with <parameter>seed</parameter> interpreted as an unsigned
+       32 bit integer.
+      </para>
+      <para>
+       If <parameter>seed</parameter> is omitted or &null;, a random unsigned
+       32-bit integer will be used.
       </para>
      </listitem>
     </varlistentry>
@@ -57,6 +63,12 @@
       </row>
      </thead>
      <tbody>
+      <row>
+       <entry>8.3.0</entry>
+       <entry>
+        <parameter>seed</parameter> is now nullable.
+       </entry>
+      </row>
       <row>
        <entry>7.1.0</entry>
        <entry>