C++: Include malloc example in qlhelp

Author: MathiasVP

cpp/ql/src/Likely Bugs/Underspecified Functions/ImplicitFunctionDeclaration.c

@@ -1,3 +1,8 @@
-void calls() {
-	undeclared_function(1, 2);
-}
+ /* '#include <stdlib.h>' was forgotton */
+
+int main(void) {
+	/* 'int malloc()' assumed */
+	unsigned char *p = malloc(100);
+    *p = 'a';
+	return 0;
+}

cpp/ql/src/Likely Bugs/Underspecified Functions/ImplicitFunctionDeclaration.qlhelp

@@ -8,14 +8,15 @@
 <p>A function is called without a prior function declaration or definition.
 When this happens, the compiler generates an implicit declaration of the function,
 specifying an integer return type and no parameters.
-</p>
+If the implicit declaration does not match the true signature of the function, the
+function may behave unpredictably.</p>
 
 <p>This may indicate a misspelled function name, or that the required header containing
 the function declaration has not been included.</p>
 
 </overview>
 <recommendation>
-<p>Ensure that the called function has been declared previously in the file or an included header file.</p>
+<p>Provide an explicit declaration of the function before invoking it.</p>
 
 </recommendation>
 <example><sample src="ImplicitFunctionDeclaration.c" />
@@ -25,4 +26,4 @@ the function declaration has not been included.</p>
 <references>
 <li>SEI CERT C Coding Standard: <a href="https://wiki.sei.cmu.edu/confluence/display/c/DCL31-C.+Declare+identifiers+before+using+them">DCL31-C. Declare identifiers before using them</a></li>
 </references>
-</qhelp>
+</qhelp>