Open System Services Programmer's Guide

• Types of parameters (OSS or Guardian) the function or macro requires.
• Types of objects (OSS or Guardian) the function or macro operates on.
G and O Notation
In the columns headed “Module Compiled As,” and “Process Called From,” the letter “G” indicates
“Guardian” and “O” indicates “OSS.”
Specified By
The “Specified By” column indicates where a function or macro is defined:
ISO
The function or macro is specified in the ISO/ANSI C standard.
POSIX
The function or macro is specified in the POSIX.1 or POSIX.2 standard. (Functions identified
as “ISO” are also specified in the POSIX.1 standard.)
HP
The function or macro is an extension specified by HP.
X/OPEN
The function or macro is specified in the XPG4 version 2 specification, which is the basis for
the X/OPEN UNIX brand.
XPG4
The function or macro is specified in the XPG4 specification. (Functions and macros identified
as “ISO” or “POSIX” are also specified in the XPG4 specification.)
Functions and macros specified in the ISO standard are declared for both Guardian and OSS
modules.
By default, functions and macros specified in POSIX, XPG4, and X/OPEN UNIX are declared only
for OSS modules. To use such a function or macro in a Guardian module (if that is allowed), specify
the _XOPEN_SOURCE feature test macro when you compile the module.
By default, functions and macros specified by HP are declared only for Guardian modules. To use
such a function or macro in an OSS module (if that is allowed), specify the _TANDEM_SOURCE
feature test macro when you compile the module.
Regardless of whether the function or macro is being called from a Guardian or OSS module,
some functions and macros specified by X/OPEN UNIX require that the
_XOPEN_SOURCE_EXTENDED feature test macro be specified when you compile the module, and
some require that either the _XOPEN_SOURCE_EXTENDED or the _TANDEM_SOURCE feature test
macro be specified when you compile the module.
For the most complete information about any function, see the reference page for that function
either online or in the Open System Services System Calls Reference Manual.
Defining Parameters and Objects
OSS parameters include OSS pathnames, stream pointers, file descriptors, signals, and process
identifiers. Guardian parameters include Guardian filenames, stream pointers, file descriptors,
signals, and process identifiers. OSS objects include OSS files, streams, and processes. Guardian
objects include Guardian files, streams, and processes.
In some cases, OSS parameters can be used to access Guardian objects. For example, an OSS
pathname parameter can identify a Guardian file using the /G/volume/subvolume/fileid
syntax.
Usage Notes
The “Usage Notes” column provides information about the behavior of the function or macro.
Unless indicated otherwise in the “Usage Notes” column, a function or macro has the same behavior
regardless of the module or process environment from which it is called.
Using the API Interoperability Table 479