diff --git a/lib/checknullpointer.cpp b/lib/checknullpointer.cpp
index 687b1de10..3435549b5 100644
--- a/lib/checknullpointer.cpp
+++ b/lib/checknullpointer.cpp
@@ -55,6 +55,7 @@ void CheckNullPointer::parseFunctionCall(const Token &tok, std::list<const Token
     // standard functions that dereference first parameter..
     static std::set<std::string> functionNames1_all;
     static std::set<std::string> functionNames1_nullptr;
+    static std::set<std::string> functionNames1_uninit;
     if (functionNames1_all.empty()) {
         // cstdlib
         functionNames1_all.insert("atoi");
@@ -106,7 +107,6 @@ void CheckNullPointer::parseFunctionCall(const Token &tok, std::list<const Token
         functionNames1_all.insert("rename");
         functionNames1_all.insert("remove");
         functionNames1_all.insert("puts");
-        functionNames1_all.insert("perror");
         functionNames1_all.insert("getc");
         functionNames1_all.insert("clearerr");
         // ctime
@@ -132,6 +132,9 @@ void CheckNullPointer::parseFunctionCall(const Token &tok, std::list<const Token
         functionNames1_nullptr.insert("gmtime");
         functionNames1_nullptr.insert("localtime");
         functionNames1_nullptr.insert("strftime");
+
+        functionNames1_uninit.insert("perror");
+        functionNames1_uninit.insert("fflush");
     }
 
     // standard functions that dereference second parameter..
@@ -184,7 +187,7 @@ void CheckNullPointer::parseFunctionCall(const Token &tok, std::list<const Token
             var.push_back(firstParam);
         else if (value == 0 && functionNames1_nullptr.find(tok.str()) != functionNames1_nullptr.end())
             var.push_back(firstParam);
-        else if (value != 0 && tok.str() == "fflush")
+        else if (value != 0 && functionNames1_uninit.find(tok.str()) != functionNames1_uninit.end())
             var.push_back(firstParam);
         else if (value == 0 && Token::Match(&tok, "snprintf|vsnprintf|fnprintf|vfnprintf") && secondParam && secondParam->str() != "0") // Only if length (second parameter) is not zero
             var.push_back(firstParam);
diff --git a/test/testnullpointer.cpp b/test/testnullpointer.cpp
index d9ad68988..89d0057cc 100644
--- a/test/testnullpointer.cpp
+++ b/test/testnullpointer.cpp
@@ -52,6 +52,7 @@ private:
         TEST_CASE(nullpointer16); // #3591
         TEST_CASE(nullpointer17); // #3567
         TEST_CASE(nullpointer18); // #1927
+        TEST_CASE(nullpointer19); // #3811
         TEST_CASE(nullpointer_castToVoid); // #3771
         TEST_CASE(pointerCheckAndDeRef);     // check if pointer is null and then dereference it
         TEST_CASE(nullConstantDereference);  // Dereference NULL constant
@@ -1250,6 +1251,13 @@ private:
         ASSERT_EQUALS("[test.cpp:5]: (error) Null pointer dereference\n", errout.str());
     }
 
+    void nullpointer19() { // #3811
+        check("int foo() {\n"
+              "    perror(0);\n"
+              "}", true);
+        ASSERT_EQUALS("", errout.str());
+    }
+
     void nullpointer_castToVoid() {  // #3771
         check("void f () {\n"
               "    int *buf = NULL;\n"
diff --git a/test/testuninitvar.cpp b/test/testuninitvar.cpp
index 706d137e0..305716954 100644
--- a/test/testuninitvar.cpp
+++ b/test/testuninitvar.cpp
@@ -1193,6 +1193,13 @@ private:
                        "};\n");
         ASSERT_EQUALS("[test.cpp:4]: (error) Data is allocated but not initialized: s\n", errout.str());
 
+        checkUninitVar("void f()\n"
+                       "{\n"
+                       "    char *s = malloc(100);\n"
+                       "    perror(s);\n"
+                       "};");
+        ASSERT_EQUALS("[test.cpp:4]: (error) Data is allocated but not initialized: s\n", errout.str());
+
         checkUninitVar("void f()\n"
                        "{\n"
                        "    char *s1 = new char[10];\n"