HP-UX SNAplus2 R7 LUA Programmer's Guide

LUA VCB Structure
LUA Verb Control Block (VCB) Format
3 LUA VCB Structure
This chapter contains details of the LUA verb control block structure used for all LUA verbs.
Symbolic constants are defined in the header files
/usr/include/sna/lua_c.h and /usr/include/sna/
values_c.h (HP-UX operating system) or sdk/winlua.h (Windows operating system)for many parameter
values. For portability, use the symbolic constant and not the numeric value when setting values for supplied
parameters, or when testing values of returned parameters. The file values_c.h also includes definitions of
parameter types such as AP_UINT16 that are used in the LUA VCBs.
Parameters marked as “reserved” should always be set to 0 (zero).
3.1 LUA Verb Control Block (VCB) Format
The verb control block consists of two parts:
• Common data structure, used for all verbs
• Specific data structure, used only for the following verbs:
• RUI_BID
• The extended version of RUI_INIT (in the HP-UX environment)
• SLI_BID
• SLI_OPEN
• SLI_SEND
The definition of some parts of the VCB structure, in particular the ordering of bit fields, varies between different
operating systems. For clarity, only one version of the ordering is shown here, although both versions are defined
in the header file. When setting or testing values in bit fields, the application should access individual bits by name,
to avoid dependencies on the bit ordering, rather than using bitwise AND or OR operations on complete bytes.
UNIX
To allow for these differences, the LUA header file contains the following information:
• A #include statement for the file /usr/include/sna/svconfig.h.
• The type definition for bit fields in the LUA data structures. This definition ensures that the data structures are
stored in the correct format. The definition depends on the setting of PUCHARQD, which is in the file /usr/
include/sna/svconfig.h.
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