The object-oriented model for input and output (I/O) is a set of classes and header files that are provided by the Standard C++ Library. These classes implement and manage the stream buffers and the data held in the buffers. Stream buffers hold data sent to the program (input) and from the program (output), enabling the program to manipulate and format the data.
There are two base classes, ios and streambuf, from which all other I/O stream classes are derived. The ios class and its derivative classes are used to implement formatting of I/O and maintain error state information of stream buffers implemented with the streambuf class.
The UNIX Systems Laboratories C++ Language System Release (USL) I/O Stream Class Library is declared in the iostream.h header file. This version does not support ASCII and large files.
The Standard C++ I/O stream classes are declared in the iostream header file. This version supports ASCII and large files. For more detailed information on the I/O stream classes provided by the Standard C++ Library, see _LARGE_FILES in z/OS XL C/C++ Language Reference.
The I/O stream classes use OBJECTMODEL(CLASSIC). They cannot be used with other classes that use OBJECTMODEL(IBM), within the same inheritance hierarchy. For more information, see OBJECTMODEL in z/OS XL C/C++ User's Guide.