Measurement Computing Personal488 rev.3.0 - Manual (Page 80)

Personal488 for Windows 95/98/Me/NT/2000 04-10-01 API Reference 6-12
DigRead
AT488pnp and PCI488 Only !
Syntax INT WINAPI DigRead(DevHandleT devHandle);
devHandle refers to an interface handle.
Returns -1 if no part of the port is configured for input, or other error
otherwise, integer between 0 and 255 if the entire digital I/O port is configured for input; or
integer between 0 and 15 if only one nibble (either low or high) is configured for input
Bus States None
Example int i = DigRead(devHandle); Returns the current value of the digital I/O
port per the current configuration.
See Also DigSetup, DigWrite
The DigRead command reads the current value of the digital IO port per the input/output configuration of
the port. If the entire port is configured for input, a value between 0 and 255 is returned. If either the
upper or lower nibble is configured for input, and the other for output, a value between 0 and 15 is
returned.
Note: This function does not configure the digital I/O port for input. The caller must use DigSetup
to configure the port for input before performing any reads. If neither nibble is configured for
input the function returns
-1 and sets the error code to IOT_BAD_VALUE2 .