Changes between Version 29 and Version 30 of Guidelines/WarningsGuidelines

Timestamp:

Aug 27, 2015, 5:06:57 PM (7 years ago)

Author:

Paul A. Bristow

Comment:

Adding note about supressing false positive from unused variables inside #ifdef ...

Guidelines/WarningsGuidelines

@@ -261 +261 @@
 d  If a warning cannot be eliminated or suppressed, explain why in the code and the documentation.  If appropriate, document in build files, as well.  Consider indicating the highest warning level possible or compiler-specific settings that will provide a warning-free build.
 
+e If a warning only appears as false positive because is it in a #ifdef, for example:
+
+{{{
+void f(int x) {
+    // ..code..
+ #ifdef XYZ
+    dostuff(x);
+#endif
+   // ..code..
+
+}}}
+
+then the compiler cannot detect that it is a false positive (FP).
+
+then it is recommended by Gabor Horvath  [http://blog.gmane.org/gmane.comp.compilers.clang.devel/day=20150827]
+to add a line like "(void) x;" to suppress the warning.
+
+Other possible workarounds (in case you have several unused variables):
+- You can use pragmas to disable some diagnostics for certain regions of code.
+- You can use compiler flags to disable some diagnostics for certain translation units.
+- You can always factor out platform dependent code to multiple files and have the #ifdef on includes.
 
 === Specific Warnings and Suggested Actions. ===
@@ -1096 +1117 @@
 [http://docs.sun.com/app/docs/doc/802-5660/6i9debhqe?a=view some Sun workarounds] to some Sun compiler errors/warnings.
 
-