Provided by: systemtap-doc_2.3-1ubuntu1.4_all 

NAME
function::user_uint8 - Retrieves an unsigned 8-bit integer value stored in user space
SYNOPSIS
user_uint8:long(addr:long)
ARGUMENTS
addr
the user space address to retrieve the unsigned 8-bit integer from
DESCRIPTION
Returns the unsigned 8-bit integer value from a given user space address. Returns zero when user space
data is not accessible.
SystemTap Tapset Reference March 2016 FUNCTION::USER_UINT8(3stap)