diff --git a/cfg/posix.cfg b/cfg/posix.cfg
index c6c66f5bf..47220c1bd 100644
--- a/cfg/posix.cfg
+++ b/cfg/posix.cfg
@@ -201,6 +201,7 @@
   <!-- void FD_CLR(int fd, fd_set *set); -->
   <function name="FD_CLR">
     <noreturn>false</noreturn>
+    <returnValue type="void"/>
     <leak-ignore/>
     <arg nr="1">
       <not-uninit/>
@@ -225,6 +226,7 @@
   <!-- void FD_SET(int fd, fd_set *set); -->
   <function name="FD_SET">
     <noreturn>false</noreturn>
+    <returnValue type="void"/>
     <leak-ignore/>
     <arg nr="1">
       <not-uninit/>
@@ -237,6 +239,7 @@
   <function name="FD_ZERO">
     <noreturn>false</noreturn>
     <leak-ignore/>
+    <returnValue type="void"/>
     <arg nr="1">
       <not-null/>
     </arg>
@@ -399,6 +402,7 @@ The obsolescent function 'usleep' is called. POSIX.1-2001 declares usleep() func
   <!-- void _exit(int status); -->
   <function name="_exit">
     <noreturn>true</noreturn>
+    <returnValue type="void"/>
     <arg nr="1">
       <not-uninit/>
     </arg>
@@ -1471,6 +1475,7 @@ The function 'mktemp' is considered to be dangerous due to race conditions and s
   <!-- void openlog(const char *ident, int option, int facility); -->
   <function name="openlog">
     <noreturn>false</noreturn>
+    <returnValue type="void"/>
     <leak-ignore/>
     <arg nr="1">
       <not-uninit/>
@@ -3642,6 +3647,7 @@ The function 'mktemp' is considered to be dangerous due to race conditions and s
   <!--  void globfree(glob_t *pglob)-->
   <function name="globfree">
     <noreturn>false</noreturn>
+    <returnValue type="void"/>
     <arg nr="1">
       <not-uninit/>
       <not-null/>
@@ -3715,9 +3721,10 @@ The function 'mktemp' is considered to be dangerous due to race conditions and s
   <!-- http://man7.org/linux/man-pages/man3/opterr.3.html-->
   <!-- int getopt(int argc, char * const argv[], const char *optstring); -->
   <function name="getopt">
-    <returnValue type="int"/>
-    <noreturn>false</noreturn>
     <leak-ignore/>
+    <noreturn>false</noreturn>
+    <returnValue type="int"/>
+    <use-retval/>
     <arg nr="1">
       <not-uninit/>
       <valid>0:</valid>
@@ -3792,6 +3799,7 @@ The function 'mktemp' is considered to be dangerous due to race conditions and s
   </function>
   <!-- void siglongjmp(sigjmp_buf env, int val); -->
   <function name="siglongjmp,_longjmp">
+    <returnValue type="void"/>
     <noreturn>true</noreturn>
     <arg nr="1">
       <not-uninit/>
@@ -3904,12 +3912,13 @@ The function 'mktemp' is considered to be dangerous due to race conditions and s
       <not-bool/>
     </arg>
   </function>
-  <!-- http://man7.org/linux/man-pages/man3/sigsetops.3.html -->
+  <!-- http://pubs.opengroup.org/onlinepubs/000095399/functions/sigismember.html -->
   <!-- int sigismember(const sigset_t *set, int signum);-->
   <function name="sigismember">
     <returnValue type="int"/>
     <noreturn>false</noreturn>
     <leak-ignore/>
+    <use-retval/>
     <arg nr="1">
       <not-null/>
     </arg>