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

NAME
function::s64_arg - Return function argument as signed 64-bit value
SYNOPSIS
s64_arg:long(n:long)
ARGUMENTS
n
index of argument to return
DESCRIPTION
Return the signed 64-bit value of argument n, same as longlong_arg.
SystemTap Tapset Reference March 2016 FUNCTION::S64_ARG(3stap)