A RetroSearch Logo

Home - News ( United States | United Kingdom | Italy | Germany ) - Football scores

Search Query:

Showing content from https://en.cppreference.com/w/cpp/language/../io/basic_stringbuf/../basic_streambuf/pubsetbuf.html below:

std::basic_streambuf<CharT,Traits>::pubsetbuf, std::basic_streambuf<CharT,Traits>::setbuf - cppreference.com

public:
basic_streambuf<CharT, Traits>* pubsetbuf( char_type* s, std::streamsize n ) (1) protected:
virtual basic_streambuf<CharT, Traits>* setbuf( char_type* s, std::streamsize n ) (2)

1) Calls setbuf(s, n) of the most derived class.

2) The base class version of this function has no effect. The derived classes may override this function to allow removal or replacement of the controlled character sequence (the buffer) with a user-provided array, or for any other implementation-specific purpose.

[edit] Parameters s - pointer to the first CharT in the user-provided buffer n - the number of CharT elements in the user-provided buffer [edit] Return value

1) The return value of setbuf(s, n).

2) this

[edit] Example

Provides a 10k buffer for reading. On linux, the strace utility may be used to observe the actual number of bytes read.

#include <fstream>
#include <iostream>
#include <string>
 
int main()
{
    int cnt = 0;
    std::ifstream file;
    char buf[1024 * 10 + 1];
 
    file.rdbuf()->pubsetbuf(buf, sizeof buf);
 
    file.open("/usr/share/dict/words");
 
    for (std::string line; getline(file, line);)
        ++cnt;
 
    std::cout << cnt << '\n';
}

Possible output:

[edit] Defect reports

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

DR Applied to Behavior as published Correct behavior LWG 158 C++98 the default behavior of setbuf was only specified
if gptr() is not null and not equal to egptr() specified as no-op
for all cases [edit] See also attempts to replace the controlled character sequence with an array
(virtual protected member function of std::basic_stringbuf<CharT,Traits,Allocator>) [edit] provides user-supplied buffer or turns this filebuf unbuffered
(virtual protected member function of std::basic_filebuf<CharT,Traits>) [edit] attempts to replace the controlled character sequence with an array
(virtual protected member function of std::strstreambuf) [edit] sets the buffer for a file stream
(function) [edit]

RetroSearch is an open source project built by @garambo | Open a GitHub Issue

Search and Browse the WWW like it's 1997 | Search results from DuckDuckGo

HTML: 3.2 | Encoding: UTF-8 | Version: 0.7.4