Content Description

This standard defines a set of system application program interfaces to operating system services. These interfaces provide access via the Ada programming language to the same operating system services for which C-language interfaces are specified in ISO/IEC 9945-1:1996 {2} ¹⁾²⁾and IEEE P1003.1g {B14}.

The purpose of this standard is to support application portability at the Ada source code level. This standard is intended to be used by both application developers and system implementors.

This standard is intended to be compatible with implementations of the 1995 revision to the Ada language standard (ISO/IEC 8652:1995 {1}). Fall-back approaches compatible with implementations of the original Ada language standard (ISO/IEC 8652:1987 {B5}) are also provided (see 1.3).

This standard is intended to contain no specifications that conflict with “Year 2000” requirements.

This standard comprises three major components:

• Definitions for terminology and concepts, and definitions and specifications that govern program structures, language-system interaction, and related requirements.
• Definitions of the specific Ada interfaces to the system services defined by the POSIX standards, presented in the form of Ada packages.
• Interpretations of Ada semantics with respect to the POSIX standards.

The following areas are outside the scope of this standard:

• User interface (shell) and commands associated with Ada program development.
• Ada bindings to the archive/interchange file formats for tar and cpio.
• Network protocols.
• Graphics and windowing interfaces.
• Database management system interfaces.
• Object or binary code portability.
• System configuration and resource availability.
• Interfaces to the Ada runtime system.

When the XTI Detailed Network Interface option and/or the Sockets Detailed Network Interface option are supported, then a set of DNI's (see 2.2.3.26) are also within the scope of this standard. A DNI is intended to provide access to protocol-specific features of the underlying network for highly portable applications that need access to sophisticated network features. The DNI's are based on the SPG4 XTI and 4.4 BSD socket specifications.

The following areas are outside of the scope of the DNI's:

• Interface to manipulate underlying protocol implementations
• Network management interface
• Interface to manipulate performance-specific features
• Definition for protocol address formats

This standard describes the external characteristics and facilities that are of importance to applications developers, rather than the implementation approaches that may be employed to achieve them. Special emphasis is placed on those facilities and capabilities needed for the broad spectrum of applications.

This standard has been defined exclusively at the source code level. The objective is that a Strictly Conforming POSIX.5 Application can be compiled to execute on any conforming implementation, within the portability of the application Ada code itself.

¹⁾ Plain numbers in curly braces correspond to those of the normative references in 1.2. Numbers preceded by a “B” in curly braces correspond to those of the bibliography in Annex A. See 2.1 for the description of this and the other typographical conventions followed in this document.

²⁾ A language-independent definitions of this standard was once under development, but work on that project was suspended.

About ISO

ISO, the International Organization for Standardization, brings global experts together to agree on the best way of doing things – for anything from making a product to managing a process. As one of the oldest non-governmental international organizations, ISO has enabled trade and cooperation between people and companies all over the world since 1946. The International Standards published by ISO serve to make lives easier, safer and better.