in8()

Read an 8-bit value from a port

Synopsis:

#include <hw/inout.h>

uint8_t in8( uintptr_t port );

Arguments:

port
The port you want to read the value from.

Library:

libc

Use the -l c option to qcc to link against this library. This library is usually included automatically.

Description:

The in8() function reads an 8-bit value from the specified port.

The calling process must use mmap_device_io() to access the device's I/O registers.

On x86 and x86_64 targets, the calling thread must have the PROCMGR_AID_IO ability enabled and must have I/O privileges, or else it will fault with a SIGSEGV; see procmgr_ability(), and the ThreadCtl() _NTO_TCTL_IO command.

Returns:

An 8-bit value.

Classification:

QNX Neutrino

Safety:  
Cancellation point No
Interrupt handler Yes
Signal handler Yes
Thread Yes