NAME¶

std::basic_stringbuf::init_buf_ptrs - std::basic_stringbuf::init_buf_ptrs

Synopsis¶

void init_buf_ptrs(); (exposition only*)

Initializes the input and output sequences from buf according to mode. buf and mode
are exposition-only data members of *this.

Immediately after this function returns:

* If std::ios_base::out is set in mode, pbase() points to buf.front() and epptr()
>= pbase() + buf.size() is true;
* in addition, if std::ios_base::ate is set in mode, pptr() == pbase() +
buf.size() is true,
* otherwise pptr() == pbase() is true.
* If std::ios_base::in is set in mode, eback() points to buf.front(), and gptr()
== eback() && egptr() == eback() + buf.size() is true.

Notes¶

For efficiency reasons, stream buffer operations can violate invariants of buf while
it is held encapsulated in the std::basic_stringbuf, e.g., by writing to characters
in the range [buf.data() + buf.size(), buf.data() + buf.capacity()).

All operations retrieving a std::basic_string from buf ensure that the
std::basic_string invariants hold on the returned value.

Defect reports

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

DR Applied to Behavior as published Correct behavior
calling init_buf_ptrs() made makes
LWG 1448 C++98 pptr() == pbase() + buf.data() pptr() == pbase() +
for streams that are both input and output buf.size()
streams for append streams