Module OS

Changes made in the current development cycle can be found in the changelog.

Description (classes)

Classes for operating system services, and assorted other things

Prerequisite

Nothing special

Review Status

Reviewed By:: Paul Shannon
Date Reviewed:: 1995/06/02/

Etymology

'OS' is the standard abbreviation for 'Operating System'.

Synopsis

This module's main purpose is to provide convenient and uniform access to operating system features: environment variables, file and directory access, time and date services, and uniform data representation (which solves the variety of ways the fundamental data types are represented in hardware).

The following functionality is available:

Class EnvironmentVariable for access to environment variables.
Class Path, RegularFile, SymLink, and Directory for dealing with the file system. Note that module IO deals with reading and writing data to files and other IO streams.
Class SysEvent for handling system events.
Class Time to get the system time.
Class Timer to measure elapsed, user, and system time of a piece of code.
Framework Conversion to convert data from one format to another. There are classes to convert to/from canonical format, VAX format, and IBM/360 format. The structure of the framework is shown in the OMT diagram.
A class to encapsulate Memory usage.

Example

See the various class header files.

Motivation

We want to provide a simple and uniform interface to OS services and features for the application and library programmer. To pick a few examples:

Recursive deletion of a directory.
Access to time and date information.
Get and set environment variables.

To Do

The OS module is a bit fuzzy: for example, canonical data format conversion is more a matter of hardware than of operating system differences. Perhaps these particular classes should be moved to a new module.
Time and Date classes should be revised after studying similar classes designed by others. Roel Martinez is tenatively scheduled to do this in the late summer of 1995.
There was once some discussion of a 'VOS' (virtual operating system) module. This seems like a good idea. Nested subdirectories for specific operating systems would contain the implementations, but a common interface would be used for all. And perhaps local site makedefs could be used to select the proper implementation to link against, with no special action required of the programmer.

Classes

CanonicalConversion -- A class with static functions to convert canonical format (full description)

CanonicalDataConversion -- A class with virtual functions to convert canonical format. (full description)

Conversion -- A class with general conversion definitions (full description)

DOos -- DO for accessing os-specific functions (full description)

DataConversion -- Abstract base class with functions to convert any format (full description)

Directory -- Get information about, and manipulate directories (full description)

DirectoryIterator -- Traverse the contents of a directory (full description)

EnvironmentVariable -- This class allows for getting enviroment variables (full description)

File -- Class to get file information and a base for other file classes. (full description)

HostInfo -- Miscellaneous information about this host and process. (full description)

HostInfo -- HostInfo for Darwin machines. (full description)

HostInfo -- HostInfo for HP-UX machines. (full description)

HostInfo -- HostInfo for IRIX machines. (full description)

HostInfo -- HostInfo for Linux machines. (full description)

HostInfo -- HostInfo for OSF1 machines. (full description)

HostInfo -- HostInfo for Solaris machines. (full description)

IBMConversion -- A class with static functions to convert IBM format (full description)

IBMDataConversion -- A class with virtual functions to convert IBM format. (full description)

LECanonicalConversion -- A class with static functions to convert little endian canonical format (full description)

LECanonicalDataConversion -- A class with virtual functions to convert little endian canonical format. (full description)

LittleEndianConversion -- A class with static functions to convert littleEndian format (full description)

Memory -- Memory related information and utilities. (full description)

ModcompConversion -- Static functions to convert Modcomp numeric formats (full description)

ModcompDataConversion -- A DataConversion class to convert between Modcomp format. (full description)

Path -- Path name of a file (full description)

PrecTimer -- Precision timer to measure elapsed times in a cumulative way (full description)

RawDataConversion -- A class with virtual functions to copy without conversion (full description)

RegularFile -- Manipulate and get information about regular files (full description)

SymLink -- Get information about, and manipulate symbolic links (full description)

SysEvent -- abstract base class for system events (from X, Glish, signals) (full description)

SysEventSource -- abstract base class for system event sources (full description)

SysEventTarget -- abstract base class for system event targets (handlers) (full description)

SysEventTargetInfo -- Internal class (full description)

Time -- date and time enquiry functions, with some operations. (full description)

Timer -- measure the time it takes to execute parts of a program (full description)

VAXConversion -- A class with static functions to convert VAX format (full description)

VAXDataConversion -- A class with virtual functions to convert VAX format (full description)

mallinfo -- A version of malloc/free/realloc written by Doug Lea. (full description)