C/C++ Programmer's Guide (G06.25+)

HP C/C++ Programmer’s Guide for NonStop Systems—429301-008

3-1

Interfacing to Guardian Procedures

and OSS Functions

•

Declaring Guardian Procedures on page 3-1

•

Calling Guardian Procedures on page 3-3

Procedures That Return a Return Value on page 3-3

Procedures That Return a Condition Code on page 3-4

Procedures With 16-Bit Addressable Parameters on page 3-6

Procedures That You Cannot Call on page 3-6

•

Declaring OSS Functions on page 3-6

This section describes how to declare and call Guardian procedures and OSS

functions in C and C++ programs.

You can (and sometimes must) use Guardian procedures when you cannot accomplish

a task with C functions. For example, to get the file code of a Guardian file, you must

use a Guardian file system procedure, such as FILE_GETINFO_ or

FILE_GETINFOBYNAME_. (See also Procedures With 16-Bit Addressable Parameters

on page 3-6.)

For information about Guardian procedures, see the Guardian Procedure Calls

Reference Manual. Some procedures in this manual are described as “superseded” by

other procedures. For example, OPEN is superseded by FILE_OPEN_. Superseded

procedures do not take full advantage of D-series or later features and you should not

use them. They are provided for backward compatibility only.

Declaring Guardian Procedures

Like all functions in a C program, Guardian procedures must be declared before they

can be called. Guardian procedures are declared as external procedures.

The library header files cextdecs (in $SYSTEM.SYSTEM in the Guardian file system)

and cextdecs.h (in /usr/include and its subdirectories in the OSS and PC file

systems) simplify the task of declaring Guardian procedures. These identical header

files contain function prototype declarations for most of the Guardian procedures that

you can call directly from C and C++ programs. These files also correspond to the TAL

and pTAL EXTDECS header file.

Other header files in $SYSTEM.SYSTEM and /usr/include also contain Guardian

procedure declarations. These header files declare Guardian procedures added in D40

or later releases and include the setjmp, tdmsigh, dlaunchh, and histryh header

files.

To determine the header file that declares the procedure, refer to a procedure’s

reference page in the Guardian Procedure Calls Reference Manual. Each procedure’s