The Open Group Base Specifications Issue 7, 2018 edition
IEEE Std 1003.1-2017 (Revision of IEEE Std 1003.1-2008)
Copyright © 2001-2018 IEEE and The Open Group
This chapter describes the contents of headers.
Headers contain function prototypes, the definition of symbolic constants, common structures, preprocessor macros, and defined
types. Each function in the System Interfaces volume of POSIX.1-2017 specifies the headers that an application shall include in
order to use that function. In most cases, only one header is required. These headers are present on an application development
system; they need not be present on the target execution system.
Format of Entries
The entries in this chapter are based on a common format as follows. The only sections relating to conformance are the SYNOPSIS
This section gives the name or names of the entry and briefly states its purpose.
This section summarizes the use of the entry being described.
This section describes the functionality of the header.
- APPLICATION USAGE
This section is informative. This section gives warnings and advice to application developers about the entry. In the event of
conflict between warnings and advice and a normative part of this volume of POSIX.1-2017, the normative material is to be taken as
This section is informative. This section contains historical information concerning the contents of this volume of POSIX.1-2017
and why features were included or discarded by the standard developers.
- FUTURE DIRECTIONS
This section is informative. This section provides comments which should be used as a guide to current thinking; there is not
necessarily a commitment to adopt these future directions.
- SEE ALSO
This section is informative. This section gives references to related information.
- CHANGE HISTORY
This section is informative. This section shows the derivation of the entry and any significant changes that have been made to
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