HP-UX SNAplus2 R7 APPC Programmer's Guide

Writing Transaction Programs
APPC Entry Points: Windows Systems
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Supplied Parameters
The supplied parameter is:
vcbptr
A pointer to the VCB structure for the verb. This parameter is defined as a long integer, and so needs to
be cast from a pointer to a long integer. For the definition of the VCB structure for each APPC verb, see
Chapter 3,
APPC Control Verbs and Chapter 4, APPC Conversation Verbs.
Note
The APPC VCBs contain many parameters marked as “reserved”; some of these are
used internally by the SNAplus2 software, and others are not used in this version
but may be used in future versions. Your application must not attempt to access any
of these reserved parameters; instead, it must set the entire contents of the VCB to
zero to ensure that all of these parameters are zero, before it sets other parameters
that are used by the verb. This ensures that SNAplus2 will not misinterpret any of
its internally-used parameters, and also that your application will continue to work
with future SNAplus2 versions in which these parameters may be used to provide
new functions.
To set the VCB contents to zero, use
memset:
memset(vcb, 0, sizeof(vcb));
Returned Values
The function does not return a value. When the call returns, the application should check the primary_rc and
secondary_rc parameters in the VCB structure to determine whether the verb completed successfully. For information
about the parameters returned in the VCB structure, see the descriptions of individual verbs in Chapter 3, APPC
Control Verbs and Chapter 4, APPC Conversation Verbs.
2.4.8 WinAPPCCancelBlockingCall
The application uses the WinAPPCCancelBlockingCall function to cancel an outstanding blocking APPC
verb (issued using the APPC entry point).
Function Call
BOOL WINAPI WinAPPCCancelBlockingCall (void);
Supplied Parameters
No parameters are supplied for this entry point. (There can be only one blocking verb outstanding at any time, so
there is no need to identify the particular verb to be canceled.)
Returned Values
The return value from the function is one of the following:
TRUE
The outstanding verb was canceled successfully.
FALSE
Either no blocking APPC verb was outstanding, or an error occurred during processing of the call and the
verb was not canceled.
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