NAME¶

std::strstreambuf::setbuf - std::strstreambuf::setbuf

Synopsis¶

protected: (deprecated in C++98)
virtual streambuf* setbuf( char* s, std::streamsize n ); (removed in C++26)

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 deallocate the dynamic member array used as the buffer
and begin using the user-supplied character array of size n, whose first element is
pointed to by s.

This function is protected virtual, it may only be called through pubsetbuf() or
from member functions of a user-defined class derived from std::strstreambuf.

Parameters¶

s - pointer to the first byte in the user-provided buffer
n - the number of bytes in the user-provided buffer

Return value¶

this

Example¶

Implementation test to check if setbuf() is supported on a dynamic strstream (output
obtained with Sun Studio):

// Run this code

#include <iostream>
#include <strstream>

int main()
{
char a[100] = {};
std::strstream str;
str.rdbuf()->pubsetbuf(a, sizeof a);
str << "Test string" << std::ends;
std::cout << "user-provided buffer holds \"" << a << "\"\n";
}

Possible output:¶

user-provided buffer holds "Test string"

Defect reports

The following behavior-changing defect reports were applied retroactively to
previously published C++ standards.

DR Applied to Behavior as published Correct behavior
the effect of setbuf() was "performs an
operation that is
LWG 66 C++98 defined separately for each class derived the effect is
from strstreambuf", implementation-defined
but there are no classes derived from
strstreambuf

See also¶

pubsetbuf invokes setbuf()
(public member function of std::basic_streambuf<CharT,Traits>)
setbuf replaces the buffer with user-defined array, if permitted
[virtual] (virtual protected member function of std::basic_streambuf<CharT,Traits>)

setbuf attempts to replace the controlled character sequence with an array
[virtual] (virtual protected member function of
std::basic_stringbuf<CharT,Traits,Allocator>)
setbuf provides user-supplied buffer or turns this filebuf unbuffered
[virtual] (virtual protected member function of std::basic_filebuf<CharT,Traits>)