std::basic_streambuf<CharT,Traits>::setp
From cppreference.com
< cpp | io | basic streambuf
| protected: void setp( char_type* pbeg, char_type* pend ); |
||
Sets the values of the pointers defining the put area.
After the call, pbase() == pbeg, pptr() == pbeg and epptr() == pend are all true.
If any of [pbeg, pend) is not a valid range, the behavior is undefined.
Parameters
| pbeg | - | pointer to the new beginning of the put area |
| pend | - | pointer to the new end of the put area |
Example
Run this code
#include <array> #include <cstddef> #include <iostream> // Buffer for std::ostream implemented by std::array template<std::size_t size, class CharT = char> struct ArrayedStreamBuffer : std::basic_streambuf<CharT> { using Base = std::basic_streambuf<CharT>; using char_type = typename Base::char_type; ArrayedStreamBuffer() { // put area pointers to work with “buffer” Base::setp(buffer.data(), buffer.data() + size); } void print_buffer() { for (char_type i : buffer) { if (i == 0) std::cout << "\\0"; else std::cout << i; std::cout << ' '; } std::cout << '\n'; } private: std::array<char_type, size> buffer{}; // value-initialize “buffer” }; int main() { ArrayedStreamBuffer<10> streambuf; std::ostream stream(&streambuf); stream << "hello"; stream << ","; streambuf.print_buffer(); }
Output:
h e l l o , \0 \0 \0 \0
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 4023 | C++98 | setp did not require the output sequence to be a valid range
|
requires |
See also
| repositions the beginning, next, and end pointers of the input sequence (protected member function) |