The classes istrstream, ostrstream, and strstream
provide some additional features for reading and writing strings in
memory--both static strings, and dynamically allocated strings. The
underlying class strstreambase provides some features common to
all three; strstreambuf underlies that in turn.
Constructor: istrstream::istrstream (const char* str [, int size])
Associate the new input string class istrstream with an existing
static string starting at str, of size size. If you do not
specify size, the string is treated as a NUL terminated string.
Constructor: ostrstream::ostrstream ()
Create a new stream for output to a dynamically managed string, which will grow as needed.
Constructor: ostrstream::ostrstream (char* str, int size [,int mode])
A new stream for output to a statically defined string of length
size, starting at str. You may optionally specify one of
the modes described for ifstream::ifstream; if you do not specify
one, the new stream is simply open for output, with mode ios::out.
Method: int ostrstream::pcount ()
Report the current length of the string associated with this ostrstream.
Method: char* ostrstream::str ()
A pointer to the string managed by this ostrstream. Implies
`ostrstream::freeze()'.
Note that if you want the string to be nul-terminated, you must do that yourself (perhaps by writing ends to the stream).
Method: void ostrstream::freeze ([int n])
If n is nonzero (the default), declare that the string associated
with this ostrstream is not to change dynamically; while frozen,
it will not be reallocated if it needs more space, and it will not be
deallocated when the ostrstream is destroyed. Use
`freeze(1)' if you refer to the string as a pointer after creating
it via ostrstream facilities.
`freeze(0)' cancels this declaration, allowing a dynamically
allocated string to be freed when its ostrstream is destroyed.
If this ostrstream is already static--that is, if it was created
to manage an existing statically allocated string---freeze is
unnecessary, and has no effect.
Method: int ostrstream::frozen ()
Test whether freeze(1) is in effect for this string.
Method: strstreambuf* strstreambase::rdbuf ()
A pointer to the underlying strstreambuf.