Keeping blank lines in C++ preproccessor output

Keeping blank lines in C++ preproccessor output

[galexander2]

I'm using the C++ preprocessor (g++ -E) to partially preprocess a C++ header file.  The preprocessor output documentation (http://gcc.gnu.org/onlinedocs/gcc-4.6.2/cpp/Preprocessor-Output.html#Preprocessor-Output) states:

  Long runs of blank lines are discarded.

Rather than have long runs of blank lines discarded, I would prefer that runs of two or more blank lines be replaced by single blank line or be left as is.  Does anyone know of a way to accomplish either of these?

Thanks,
Geoff Alexander

Re: Keeping blank lines in C++ preproccessor output

[Ian Lance Taylor]

<galexander2@nc.rr.com> writes:

> I'm using the C++ preprocessor (g++ -E) to partially preprocess a C++ header file.  The preprocessor output documentation (http://gcc.gnu.org/onlinedocs/gcc-4.6.2/cpp/Preprocessor-Output.html#Preprocessor-Output) states:
>
>   Long runs of blank lines are discarded.
>
> Rather than have long runs of blank lines discarded, I would prefer that runs of two or more blank lines be replaced by single blank line or be left as is.  Does anyone know of a way to accomplish either of these?

As far as I know there is no way to do this (other than modifying the
preprocessor code).  It would not be too hard to write a postprocessor
which looked at the #line statements and recreated the blank lines.

Ian

Re: Keeping blank lines in C++ preproccessor output

[Kevin P. Fleming]

On 01/07/2012 01:05 PM, Ian Lance Taylor wrote:
> <galexander2@nc.rr.com>  writes:
>
>> I'm using the C++ preprocessor (g++ -E) to partially preprocess a C++ header file.  The preprocessor output documentation (http://gcc.gnu.org/onlinedocs/gcc-4.6.2/cpp/Preprocessor-Output.html#Preprocessor-Output) states:
>>
>>    Long runs of blank lines are discarded.
>>
>> Rather than have long runs of blank lines discarded, I would prefer that runs of two or more blank lines be replaced by single blank line or be left as is.  Does anyone know of a way to accomplish either of these?
>
> As far as I know there is no way to do this (other than modifying the
> preprocessor code).  It would not be too hard to write a postprocessor
> which looked at the #line statements and recreated the blank lines.

You could also use MCPP if you wish to roll your own preprocessing tool 
with more control over the output.

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Keeping blank lines in C++ preproccessor output

[galexander2]

I'm using the C++ preprocessor (g++ -E) to partially preprocess a C++ header file.  The preprocessor output documentation (http://gcc.gnu.org/onlinedocs/gcc-4.5.1/cpp/Preprocessor-Output.html) states:

  Long runs of blank lines are discarded.

Rather than have long runs of blank lines discarded, I would prefer that runs of two or more blank lines be replaced by single blank line or that blank lines be left as is.  Does anyone know of a way to accomplish either of these?

Thanks,
Geoff Alexander