std::basic_stringbuf<CharT,Traits,Allocator>:: setbuf
protected
:
virtual std:: basic_streambuf < CharT, Traits > * setbuf ( char_type * s, std:: streamsize n ) |
||
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
.
Parameters
s | - | pointer to the first CharT in the user-provided buffer or null |
n | - | the number of CharT elements in the user-provided buffer or zero |
Return value
this
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.
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++)
See also
invokes
setbuf
(
)
(public member function of
std::basic_streambuf<CharT,Traits>
)
|