Guardian Procedure Calls Reference Manual (G06.25+)

Introduction to Guardian Procedure Calls

Guardian Procedure Calls Reference Manual—522629-013

1-12

C Syntax for a Guardian Procedure Call

C syntax is presented in this manual in addition to TAL syntax. Where necessary,

considerations for C programmers are also presented. For further information on

calling Guardian procedures from a C program, refer to the

C/C++ Programmer’s

Guide.

Figure 1-3

shows an example of C syntax. As in TAL syntax, square brackets ([ ])

indicate optional parameters. Detailed descriptions of parameters are not included with

the C syntax; such descriptions accompany the TAL syntax.

Because TAL does not have a string terminator like C, it often requires that you supply

both a string and its length (not counting the null-byte terminator) in two parameters, or

that you supply a string buffer with the maximum string length along with a third

parameter for returning the actual string length (see “String Output Variables,” earlier in

this section).

When calling TAL procedures that use strings in this manner from a C program, you

must also pass the complete set of parameters for handling the string. The TAL

convention of pairing certain string parameters together, joined by colons, is not

supported in C; parameters are always separated by commas.

C Header Files

To support portability from the UNIX environment, the name of a C header file can

contain an internal period (.). The HP C for NonStop Systems compiler accepts both of

the following statements as equivalent:

#include <stdio.h>

#include <stdioh>

Actual C header files are stored on the same subvolume as the C compiler with no

internal periods in their names. If the C compiler on your system is

$SYSTEM.SYSTEM.C, then your system should have the header file

$SYSTEM.SYSTEM.STDIOH.

CEXTDECS in H-Series Systems

In H-series systems, CEXTDECS (through the included file TNSINTH) defines 32-bit

values as the

typedef __int32_t which for TNS and TNS/R compiles is defined as long

and for TNS/E compiles is defined as

int.

Figure 1-3. Sample C Syntax for a Procedure Call

#include <cextdecs(BREAKMESSAGE_SEND_)>

short BREAKMESSAGE_SEND_ ( short *processhandle

,short receiver-filenum

,[ short *breaktag ] );