diff --git a/lib/checkother.cpp b/lib/checkother.cpp
index 3c3a874cf..b944a3df7 100644
--- a/lib/checkother.cpp
+++ b/lib/checkother.cpp
@@ -333,7 +333,7 @@ static std::string analyzeType(const Token* tok)
     }
     if (tok->str() == "float")
         return "float";
-    if (Token::Match(tok, "unsigned| int|long|short|char|size_t"))
+    if (Token::Match(tok, "int|long|short|char|size_t"))
         return "integer";
     return "";
 }
@@ -398,16 +398,19 @@ void CheckOther::invalidPointerCast()
 
         std::string fromType = analyzeType(fromTok);
         std::string toType = analyzeType(toTok);
-        if (fromType != toType && !fromType.empty() && !toType.empty() && (toType != "integer" || _settings->isEnabled("portability")))
-            invalidPointerCastError(tok, fromType, toType);
+        if (fromType != toType && !fromType.empty() && !toType.empty() && (toType != "integer" || _settings->isEnabled("portability")) && (toTok->str() != "char" || _settings->inconclusive))
+            invalidPointerCastError(tok, fromType, toType, toTok->str() == "char");
     }
 }
 
-void CheckOther::invalidPointerCastError(const Token* tok, const std::string& from, const std::string& to)
+void CheckOther::invalidPointerCastError(const Token* tok, const std::string& from, const std::string& to, bool inconclusive)
 {
-    if (to == "integer") // If we cast something to int*, this can be useful to play with its binary data representation
-        reportError(tok, Severity::portability, "invalidPointerCast", "Casting from " + from + "* to integer* is not portable due to different binary data representations on different platforms");
-    else
+    if (to == "integer") { // If we cast something to int*, this can be useful to play with its binary data representation
+        if (!inconclusive)
+            reportError(tok, Severity::portability, "invalidPointerCast", "Casting from " + from + "* to integer* is not portable due to different binary data representations on different platforms");
+        else
+            reportInconclusiveError(tok, Severity::portability, "invalidPointerCast", "Casting from " + from + "* to char* might be not portable due to different binary data representations on different platforms");
+    } else
         reportError(tok, Severity::warning, "invalidPointerCast", "Casting between " + from + "* and " + to + "* which have an incompatible binary data representation");
 }
 
diff --git a/lib/checkother.h b/lib/checkother.h
index f0377ecf3..74d709a22 100644
--- a/lib/checkother.h
+++ b/lib/checkother.h
@@ -268,7 +268,7 @@ private:
     void invalidPrintfArgTypeError_int(const Token* tok, unsigned int numFormat, char c);
     void invalidPrintfArgTypeError_float(const Token* tok, unsigned int numFormat, char c);
     void cstyleCastError(const Token *tok);
-    void invalidPointerCastError(const Token* tok, const std::string& from, const std::string& to);
+    void invalidPointerCastError(const Token* tok, const std::string& from, const std::string& to, bool inconclusive);
     void dangerousUsageStrtolError(const Token *tok);
     void sprintfOverlappingDataError(const Token *tok, const std::string &varname);
     void udivError(const Token *tok, bool inconclusive);
@@ -331,7 +331,7 @@ private:
         c.sizeofForNumericParameterError(0);
         c.coutCerrMisusageError(0, "cout");
         c.doubleFreeError(0, "varname");
-        c.invalidPointerCastError(0, "float", "double");
+        c.invalidPointerCastError(0, "float", "double", false);
 
         // style/warning
         c.cstyleCastError(0);
diff --git a/test/testother.cpp b/test/testother.cpp
index 490b9b27e..6fc8707bb 100644
--- a/test/testother.cpp
+++ b/test/testother.cpp
@@ -783,7 +783,7 @@ private:
         ASSERT_EQUALS("", errout.str());
     }
 
-    void checkInvalidPointerCast(const char code[], bool portability = false) {
+    void checkInvalidPointerCast(const char code[], bool portability = false, bool inconclusive = false) {
         // Clear the error buffer..
         errout.str("");
 
@@ -791,6 +791,7 @@ private:
         settings.addEnabled("style");
         if (portability)
             settings.addEnabled("portability");
+        settings.inconclusive = inconclusive;
 
         // Tokenize..
         Tokenizer tokenizer(&settings, this);
@@ -849,6 +850,16 @@ private:
                                 "}");
         ASSERT_EQUALS("[test.cpp:2]: (warning) Casting between double* and float* which have an incompatible binary data representation\n", errout.str());
 
+        checkInvalidPointerCast("void test(float* data) {\n" // #3639
+                                "    f.write((char*)data,sizeof(float));\n"
+                                "}", true, false);
+        ASSERT_EQUALS("", errout.str());
+
+        checkInvalidPointerCast("void test(float* data) {\n"
+                                "    f.write((char*)data,sizeof(float));\n"
+                                "}", true, true);
+        ASSERT_EQUALS("[test.cpp:2]: (portability) Casting from float* to char* might be not portable due to different binary data representations on different platforms\n", errout.str());
+
 
         checkInvalidPointerCast("long long* test(float* f) {\n"
                                 "    return (long long*)f;\n"