posix.cfg: Improved configuration of recv().

cfg/posix.cfg

@@ -2261,6 +2261,7 @@ The function 'mktemp' is considered to be dangerous due to race conditions and s
       <valid>0:</valid>
     </arg>
     <arg nr="2" direction="out">
+      <not-null/>
       <minsize type="argvalue" arg="3"/>
     </arg>
     <arg nr="3" direction="in">

test/cfg/posix.c

@@ -32,6 +32,13 @@
 #include <wchar.h>
 #include <string.h>
 
+ssize_t nullPointer_recv(int sockfd, void *buf, size_t len, int flags)
+{
+    // cppcheck-suppress nullPointer
+    (void) recv(sockfd, NULL, len, flags);
+    return recv(sockfd, buf, len, flags);
+}
+
 ssize_t nullPointer_recvfrom(int sockfd, void *buf, size_t len, int flags,
                              struct sockaddr *src_addr, socklen_t *addrlen)
 {