Read an 8-bit value from a port
#include <hw/inout.h> uint8_t in8( uintptr_t port );
libc
Use the -l c option to qcc to link against this library. This library is usually included automatically.
The in8() function reads an 8-bit value from the specified port.
An 8-bit value.
Safety: | |
---|---|
Cancellation point | No |
Interrupt handler | Yes |
Signal handler | Yes |
Thread | Yes |
The calling thread must have the PROCMGR_AID_IO ability enabled and must have I/O privileges; see procmgr_ability(), and ThreadCtl()'s _NTO_TCTL_IO command for details.
The calling process must also use mmap_device_io() to access the device's I/O registers.