Compaq AAPVNFGTE manual Return Status, Session Environments, Parameter-Passing Mechanisms

Table 1–4 Parameter-Passing Mechanisms

Mechanism	Description
By value	The parameter contains a copy of the data to be used by the routine.
By reference	The parameter contains the address of the data to be used by
	the routine. The parameter is a pointer to the data. Because C
	supports only call by value, write parameters other than arrays
	and structures must be passed as pointers. References to names
	of arrays and structures are converted by the compiler to pointer
	expressions.

For information on whether the caller or the called routine allocates memory, see the discussions of the individual platforms.

1.4 Return Status

Each service returns a status value defined as follows:

Platform	Value
Windows	long int
OpenVMS	long int
Tru64 UNIX	long int

Only the status codes defined in the related reference sections are valid in the TP Desktop Connector client services. The definitions for the return status values are in include files as follows:

Type of Services	Include File
Portable client services	ACMSDI$COMMON:ACMSDI.H

1.5 Session Environments

Client services can be used in three different session environments, blocking, nonblocking, and forced nonblocking. In a blocking environment, service routines are completed in one procedure. In a nonblocking environment, service routines return control to the desktop client program as soon as a request is sent and then call the appropriate completion routine when the request is completed or call the appropriate presentation procedure when an exchange step is detected.

1–4Service Format