#5645 False positive Null pointer derefence about first argument to fputc()

cfg/std.cfg

@@ -42,7 +42,7 @@
   <function name="fputc">
        <noreturn>false</noreturn>
        <leak-ignore/>
-       <arg nr="1"><not-null/><not-uninit/><not-bool/><valid>0-</valid></arg>
+       <arg nr="1"><not-uninit/><not-bool/><valid>0-</valid></arg>
        <arg nr="2"><not-null/><not-uninit/></arg>
   </function>
   <function name="fputs">

test/testnullpointer.cpp

@@ -82,6 +82,7 @@ private:
         TEST_CASE(crash1);
         TEST_CASE(functioncallDefaultArguments);
         TEST_CASE(nullpointer_internal_error); // #5080
+        TEST_CASE(nullpointerFputc);     //  #5645 FP: Null pointer dereference in fputc argument
 
         // Test that std.cfg is configured correctly
         TEST_CASE(stdcfg);
@@ -2534,6 +2535,25 @@ private:
         check("void f(char * p,char * q){ strtol (p,q,0);if(!p){}}");
         ASSERT_EQUALS(errp,errout.str());
     }
+
+    void nullpointerFputc() {
+        check("int main () {\n"
+            "FILE *fp = fopen(\"file.txt\", \"w+\");\n"
+            "fputc(000, fp);   \n"
+            "fclose(fp);\n"
+            "return 0 ;\n"
+            "}\n");
+        ASSERT_EQUALS("", errout.str());
+
+        check("int main () {\n"
+            "FILE *fp = fopen(\"file.txt\", \"w+\");\n"
+            "char *nullstring=0;"
+            "fputc(*nullstring, fp);   \n"
+            "fclose(fp);\n"
+            "return 0 ;\n"
+            "}\n");
+        ASSERT_EQUALS("[test.cpp:3]: (error) Possible null pointer dereference: nullstring\n", errout.str());
+    }
 };
 
 REGISTER_TEST(TestNullPointer)