diff --git a/cfg/posix.cfg b/cfg/posix.cfg
index c33a774af..38bab9fec 100644
--- a/cfg/posix.cfg
+++ b/cfg/posix.cfg
@@ -837,7 +837,7 @@
   <!-- pid_t setsid(void); -->
   <function name="setsid">
     <noreturn>false</noreturn>
-    <use-retval/>
+    <!-- it is a good idea to do: <use-retval/> -->
   </function>
   <!-- char *getwd(char *path_name);-->
   <function name="getwd">
@@ -1047,6 +1047,21 @@
   <function name="setpwent">
     <noreturn>false</noreturn>
   </function>
+  <!-- http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/poll.h.html -->
+  <!-- int   poll(struct pollfd [], nfds_t, int); -->
+  <function name="poll">
+    <noreturn>false</noreturn>
+    <use-retval/>
+    <arg nr="1">
+      <not-uninit/>
+    </arg>
+    <arg nr="2">
+      <not-uninit/>
+    </arg>
+    <arg nr="3">
+      <not-uninit/>
+    </arg>
+  </function>
   <!-- http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/regex.h.html -->
   <podtype name="regex_t"/>
   <!-- int    regcomp(regex_t *, const char *, int); -->
@@ -1066,16 +1081,11 @@
   <function name="regerror">
     <noreturn>false</noreturn>
     <arg nr="1">
-      <not-null/>
       <not-uninit/>
     </arg>
     <arg nr="2">
       <not-uninit/>
     </arg>
-    <arg nr="3">
-      <not-null/>
-      <not-uninit/>
-    </arg>
     <arg nr="4">
       <not-uninit/>
     </arg>
diff --git a/test/cfg/posix.c b/test/cfg/posix.c
index eed6e10c1..1decaf1be 100644
--- a/test/cfg/posix.c
+++ b/test/cfg/posix.c
@@ -150,6 +150,7 @@ void uninitvar(int fd) {
     pattern="";
     // cppcheck-suppress uninitvar
     regcomp(&reg, pattern, cflags);
+    regerror (0, &reg, 0, 0);
     // cppcheck-suppress uninitvar
     // cppcheck-suppress unreadVariable
     char *buffer = ecvt(d, 11, &decimal, &sign);