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.
1–4 Service Format
