std::basic_stringbuf::setbuf
| protected:
virtual std::basic_streambuf<CharT, Traits>* setbuf( char_type* s, std::streamsize n ) |
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If s is a null pointer and n is zero, this function has no effect.
Otherwise, the effect is implementation-defined: some implementations do nothing, while some implementations clear the std::string member currently used as the buffer and begin using the user-supplied character array of size n, whose first element is pointed to by s, as the buffer and the input/output character sequence.
This function is protected virtual, it may only be called through pubsetbuf() or from member functions of a user-defined class derived from std::basic_stringbuf.
Contents |
[edit] Parameters
| s | - | pointer to the first byte in the user-provided buffer or null |
| n | - | the number of bytes in the user-provided buffer or zero |
[edit] Return value
*this, cast to the base class std::basic_streambuf.
[edit] Notes
The deprecated stream buffer std::strstreambuf or the boost.IOStreams device boost::basic_array may be used to implement I/O buffering over a user-provided char array in portable manner.
[edit] Example
Test for the stringstream's setbuf functionality
#include <iostream> #include <sstream> int main() { std::ostringstream ss; char c[1024] = {}; ss.rdbuf()->pubsetbuf(c, 1024); ss << 3.14 << '\n'; std::cout << c << '\n'; }
Output:
3.14 (on GNU g++/libstdc++ and SunPro C++/roguewave) <nothing> (on MS Visual Studio 2010, SunPro C++/stlport4, CLang++/libc++)
[edit] See also
| invokes setbuf() (public member function of std::basic_streambuf)
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