diff --git a/cfg/posix.cfg b/cfg/posix.cfg
index c8dca78bf..585e06a3d 100644
--- a/cfg/posix.cfg
+++ b/cfg/posix.cfg
@@ -1800,6 +1800,26 @@ The function 'mktemp' is considered to be dangerous due to race conditions and s
       <not-bool/>
     </arg>
   </function>
+  <!-- int socketpair(int domain, int type, int protocol, int sv[2]); -->
+  <function name="socketpair">
+    <returnValue type="int"/>
+    <noreturn>false</noreturn>
+    <arg nr="1" direction="in">
+      <not-uninit/>
+    </arg>
+    <arg nr="2" direction="in">
+      <not-uninit/>
+    </arg>
+    <arg nr="3" direction="in">
+      <not-uninit/>
+    </arg>
+    <arg nr="4" direction="out">
+      <not-null/>
+      <not-bool/>
+      <minsize type="value" value="2"/>
+    </arg>
+  </function>
+  <!-- http://man7.org/linux/man-pages/man2/socketpair.2.html -->
   <!-- int pipe(int fildes[2]); -->
   <function name="pipe">
     <returnValue type="int"/>