[Boost-users] Serialization, mpl: BOOST_CLASS_VERSION() macro causes gcc compile errors with Boost version 1.43

Subject: [Boost-users] Serialization, mpl: BOOST_CLASS_VERSION() macro causes gcc compile errors with Boost version 1.43
From: Clarke, Carus V (carus.v.clarke_at_[hidden])
Date: 2010-06-24 13:40:55

Using Boost version 1.43 to compile my project caused the following errors to occur.  There are more, but they are essentially the same:

g++ -o build/ftds_com/calc/DerivedCalculationInformation.o -c -Wall -ansi -Wno-missing-braces -mwin32 -mthreads -DZAF_BOOL_DEFINED -D_WIN32_WINNT=0x0501 -D__USE_W32_SOCKETS -DWIN32_LEAN_AND_MEAN -DNOMINMAX -Iinclude -I/c/dvlp/boost_1_43_0 -I/c/dvlp/vt1413_32/include "-I/c/Program Files/IVI Foundation/VISA/winnt/include" "-I/c/Program Files/Agilent/IO Libraries Suite/include" -I/c/dvlp/zaf6.0/target/h source/ftds_com/calc/DerivedCalculationInformation.cpp
In file included from source/ftds_com/calc/DerivedCalculationInformation.cpp:27:
include/avgcalc.h:67: error: conflicting declaration 'mpl_assertion_in_line_67'
include/addcalc.h:67: error: 'mpl_assertion_in_line_67' has a previous declaration as '<anonymous enum> mpl_assertion_in_line_67'
In file included from source/ftds_com/calc/DerivedCalculationInformation.cpp:35:
include/dselcalc.h:68: error: conflicting declaration 'mpl_assertion_in_line_68'
include/actual_airflow_calc.h:68: error: 'mpl_assertion_in_line_68' has a previous declaration as '<anonymous enum> mpl_assertion_in_line_68'
In file included from source/ftds_com/calc/DerivedCalculationInformation.cpp:36:
include/epowcalc.h:65: error: conflicting declaration 'mpl_assertion_in_line_65'
include/datecalc.h:65: error: 'mpl_assertion_in_line_65' has a previous declaration as '<anonymous enum> mpl_assertion_in_line_65'
In file included from source/ftds_com/calc/DerivedCalculationInformation.cpp:37:
include/fsdvcalc.h:68: error: conflicting declaration 'mpl_assertion_in_line_68'
include/actual_airflow_calc.h:68: error: 'mpl_assertion_in_line_68' has a previous declaration as '<anonymous enum> mpl_assertion_in_line_68'
In file included from source/ftds_com/calc/DerivedCalculationInformation.cpp:38:
include/gas_density_calc.h:68: error: conflicting declaration 'mpl_assertion_in_line_68'
...

I was able to verify that these were caused by the BOOST_CLASS_VERSION macro appearing on the same line in two or more files included by the file being compiled.  Using the BOOST_PP_COUNTER from the preprocessor library as the argument to a #line directive on the line preceding the BOOST_PP_COUNTER macro can be used as a workaround.  Another was to disable the MPL assertion in the body of the macro.  For class versioning to work for gcc, the BOOST_PP_COUNTER macro has to appear in a header file, and I think it is better to put it in the header files for the classes to be serialized.

Here is a sample of the workaround:

// the next two lines are needed to prevent compile-time errors with gcc
#include BOOST_PP_UPDATE_COUNTER()
#line BOOST_PP_COUNTER
BOOST_CLASS_VERSION(Calculation, 0)

Is there a better way to handle the problem?   Is this a bug?

Thanks,

Carus V. (Bud) Clarke
carus.v.clarke_at_[hidden]