76 lines
1.5 KiB
Plaintext
76 lines
1.5 KiB
Plaintext
////
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Copyright 2021 Glen Joseph Fernandes
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(glenjofe@gmail.com)
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Distributed under the Boost Software License, Version 1.0.
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(http://www.boost.org/LICENSE_1_0.txt)
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////
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# Null Streams, <boost/io/nullstream.hpp>
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:toc:
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:toc-title:
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:idprefix:
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## Description
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The header `<boost/io/nullstream.hpp>` provides the class template
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`boost::io::basic_nullbuf` which is a null stream buffer and class template
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`boost::io::basic_onullstream` which is a null stream.
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## Example
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The following program passes a null stream to a function.
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```
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#include <boost/io/ostream_joiner.hpp>
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#include <fstream>
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void setup(std::ostream& log);
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int main(int argc, char* argv[])
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{
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if (argc == 2) {
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std::ofstream file(argv[1]);
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setup(file);
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} else {
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boost::io::onullstream none;
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setup(none);
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}
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}
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```
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## Reference
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### Header Synopsis
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```
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namespace boost {
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namespace io {
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template<class CharT, class Traits = std::char_traits<Char> >
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class basic_nullbuf
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: public std::basic_streambuf<CharT, Traits> {
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protected:
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typename Traits::int_type overflow(typename Traits::int_type c) override;
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std::streamsize xsputn(const CharT*, std::streamsize n) override;
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};
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template<class CharT, class Traits = std::char_traits<CharT> >
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class basic_onullstream
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: public std::basic_ostream<CharT, Traits> {
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public:
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basic_onullstream();
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};
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typedef basic_onullstream<char> onullstream;
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typedef basic_onullstream<wchar_t> wonullstream;
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} // io
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} // boost
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```
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## Acknowledgments
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Glen Fernandes implemented `basic_nullbuf` and `basic_onullstream`.
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