NAME¶

std::basic_streambuf::pbump - std::basic_streambuf::pbump

Synopsis¶

protected:
void pbump( int count );

Repositions the put pointer (pptr()) by count characters, where count may be
positive or negative. No checks are done for moving the pointer outside the put area
[pbase(), epptr()).

If the pointer is advanced and then overflow() is called to flush the put area to
the associated character sequence, the effect is that extra count characters with
undefined values are output.

Parameters¶

count - number to add to the put pointer

Return value¶

(none)

Notes¶

Because this function takes an int, it cannot manipulate buffers larger than
std::numeric_limits<int>::max() characters (LWG issue 255).

Example¶

// Run this code

#include <fstream>
#include <iostream>
#include <string>

struct showput_streambuf : std::filebuf
{
using std::filebuf::pbump; // expose protected
std::string showput() const
{
return std::string(pbase(), pptr());
}
};

int main()
{
showput_streambuf mybuf;
mybuf.open("test.txt", std::ios_base::out);
std::ostream str(&mybuf);
str << "This is a test" << std::flush << "1234";
std::cout << "The put area contains: " << mybuf.showput() << '\n';
mybuf.pbump(10);
std::cout << "after pbump(10), it contains " << mybuf.showput() << '\n';
}

Output:¶

The put area contains: 1234
after pbump(10), it contains 1234 is a test

See also¶

gbump advances the next pointer in the input sequence
(protected member function)