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ExpMgrIOReadByte

You can use the ExpMgrIOReadByte function to read the byte value at a specific address in PCI I/O space.



 
OSErr ExpMgrIOReadByte (

                     RegEntryIDPtr node,

                     LogicalAddress ioAddr,

                     UInt8 *valuePtr);

node: A node identifier that identifies a device node. If you specify a node identifier that isn't in the device tree, ExpMgrIOReadByte returns a result code of deviceTreeInvalidNodeErr.
ioAddr: The sum of the assigned-addresses base address of the device plus the offset to the desired I/O address.
valuePtr: The returned 8-bit value.

DESCRIPTION

The ExpMgrIOReadByte function reads the byte at the I/O address for device node node determined by address ioAddr, returning its byte-swapped value in valuePtr.

RESULT CODES

`noErr`	0	No error
`deviceTreeInvalidNodeErr`	-2538	Device node not in the device tree