std::basic_stringbuf<CharT,Traits,Allocator>:: init_buf_ptrs
|
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 |
|---|---|---|---|
| LWG 1448 | C++98 |
calling
init_buf_ptrs
()
made
pptr ( ) == pbase ( ) + buf. data ( ) for streams that are both input and output streams |
makes
pptr ( ) == pbase ( ) + buf. size ( ) for append streams |