[Overview][Procedures and functions][Index] | Reference for unit 'x86' (#rtl)

# ReadPort

Read data from a PC port

## Declaration

Source position: x86.pp line 27

`procedure ReadPort(`
`Port: LongInt;`
`var Value: Byte`
`); procedure ReadPort(`
`Port: LongInt;`
`var Value: LongInt`
`); procedure ReadPort(`
`Port: LongInt;`
`var Value: Word`
`);`

## Description

ReadPort reads one Byte, Word or Longint from port Port into Value.

Note that you need permission to read a port. This permission can be set by the root user with the FpIOPerm call.

## Errors

In case of an error (not enough permissions read this port), runtime 216 ( Access Violation) will occur.

## See also

FpIOPerm |  | Set permission on IO ports
ReadPortB |  | Read bytes from a PC port
ReadPortW |  | Read Words from a PC port
ReadPortL |  | Read longints from a PC port
WritePort |  | Write data to PC port
WritePortB |  | Write byte to PC port
WritePortL |  | Write longint to PC port.
WritePortW |  | Write Word to PC port