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Programming Example
Programming in C using the VTL
Next, you open a session with a specific device with the viOpen
function. This function uses the session returned from
viOpenDefaultRM and returns its own session to identify the device
session. The following shows the function syntax:
viOpenDefaultRM (sesn);
viOpen (sesn, rsrcName, accessMode, timeout, vi);
The session returned from viOpenDefaultRM must be used in the
sesn parameter of the viOpen function. The viOpen function then
uses that session and the device address specified in the (resource
name) parameter to open a device session. The vi parameter in
viOpen returns a session identifier that can be used with other VTL
functions.
Your program may have several sessions open at the same time by
creating multiple session identifiers by calling the viOpen function
multiple times.
The following summarizes the parameters in the previous function
calls:
sesn
This is a session returned from the viOpenDefaultRM function that identifies the
resource manager session.
rsrcName
This is a unique symbolic name of the device (device address).
accessMode
This parameter is not used for VTL. Use VI_NULL.
timeout
This parameter is not used for VTL. Use VI_NULL.
vi
This is a pointer to the session identifier for this particular device session. This pointer
will be used to identify this device session when using other VTL functions.
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