0000832: Adding -pedantic compiler option triggers warnings in OMNeT++ headers

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Date Submitted

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0000832

OMNeT++

IDE / C++ development

public

2015-08-12 20:09

2017-02-13 12:30

Reporter

woife

Assigned To

rhornig

Priority

low

Severity

minor

Reproducibility

always

Status

resolved

Resolution

fixed

Platform

Windows and Linux

OS Version

Product Version

4.6

Target Version

Fixed in Version

5.1pre3

Summary

0000832: Adding -pedantic compiler option triggers warnings in OMNeT++ headers

Description

I wanted to use the compiler option -pedantic in one of my projects.
But compiling the project with this options overflows to console window with lots of warnings generated by some OMNeT++ headers.

All of these warnings are of the same type (warning: extra ‘;’) and are triggered by only 2 places in the code:

Place 1: nedsupport.h
--------------------------

This file contains the definition of the namespace 'NEDSupport', which ends at the end of the file, and is terminated with a semicolon. This semicolon is not necessary, triggers a warning, and can be safely removed.

Place 2: onstartup.h
--------------------------

This is more difficult. I can describe why the warning triggers, but I don't know how to fix it.

Suppose you have a message file name MyMessages.msg with a message type called MyMessage. Compiling this file creates a C++ file called MyMessages_m.cc.

This file will contain the lines
Register_Class(MyMessage);
and
Register_ClassDescriptor(MyMessageDescriptor);

These macros are defined in 'regmacros.h' and both contain as their last statement the macro EXECUTE_ON_STARTUP which is defined in 'onstartup.h'.

The code in EXECUTE_ON_STARTUP defines a namespace which is again followed by a semicolon. Again, this semicolon is not necessary and can be removed.

However, this time this is not enough: When the Register_Class macro is expanded, the semicolon after Register_Class in the original C++ File (MyMessage_m.cc) will follow right after the namespace definition, where it triggers the same warning.

I don't know how to fix this. As a very dirty workaround, I have added the following statement at the end of EXECUTE_ON_STARTUP:
struct MAKE_UNIQUE_WITHIN_FILE(dirty_workaround_for_compiler_warning)

This gets rid of the warning, and I can compile my code with -pedantic without a single warning. However, the intention of adding -pedantic is to write clean code, so adding dirty hacks is probably not a good way to shut down a warning :)

It hasn't triggered a warning with my code, but the macro EXECUTE_ON_SHUTDOWN has the same structure as EXECUTE_ON_STARTUP, so I guess changes for one should also be applied to the other.

Additional Information

To add the compiler option -pedantic, I added the following text in project settings->OMNeT++->Makemake->Options->Custom->Makefrag:

CXXFLAGS += -pedantic

Notes
(0001316) rhornig (administrator) 2017-02-13 12:30	Pragmas were added to mute expected warnings in OMNeT++ code.

Issue History
Date Modified	Username	Field	Change
2015-08-12 20:09	woife	New Issue
2015-10-12 10:28	ammmar1988	Issue cloned: 0000842
2017-02-13 12:30	rhornig	Note Added: 0001316
2017-02-13 12:30	rhornig	Status	new => resolved
2017-02-13 12:30	rhornig	Fixed in Version	=> 5.1pre3
2017-02-13 12:30	rhornig	Resolution	open => fixed
2017-02-13 12:30	rhornig	Assigned To	=> rhornig

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