HP Integrity NonStop J-Series - Manual (Page 74)

Inheriting from RWvios are the abstract base classes RWvistream and RWvostream . These
classes declare a suite of pure virtual functions such as operator<<(), put(), get(), and the like,
for all the basic built-in types and arrays of built-in types:
class RWvistream : public RWvios {
public:
virtual Rwvistream& operator>>(char&) = 0;
virtual Rwvistream& operator>>(double&) = 0;
virtual int get() = 0;
virtual Rwvistream& get(char&) = 0;
virtual Rwvistream& get(double&) = 0;
virtual Rwvistream& get(char*, size_t N) = 0;
virtual Rwvistream& get(double*, size_t N) = 0;
.
.
.
};
class RWvostream : public RWvios {
public:
virtual Rwvostream& operator<<(char) = 0;
virtual Rwvostream& operator<<(double) = 0;
virtual Rwvostream& put(char) = 0;
virtual Rwvostream& put(double) = 0;
virtual Rwvostream& put(const char*, size_t N) = 0;
virtual Rwvostream& put(const double*, size_t N) = 0;
.
.
.
};
Streams that inherit from RWvistream and RWvostream are intended to store built-ins to
specialized streams in a format that is transparent to the user of the classes.
The basic abstraction of the virtual streams facility is that built-ins are inserted into a virtual
output stream, and extracted from a virtual input stream, without any regard for formatting. In
other words, there is no need to pad output with whitespace, commas, or any other kind of
formatting. You are effectively telling
RWvostream , "Here is a double. Please store it for me in
whatever format is convenient, and give it back to me in good shape when I ask for it."
The results are extremely powerful. You can write and use streaming operators without
knowing anything about the final output medium or formatting to be used. For example, the
output medium could be a disk, memory allocation, or even a network. The formatting could be
in binary, ASCII, or network packet. In all of these cases, you use the same streaming operators.