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

NAME
function::return_str - Formats the return value as a string
SYNOPSIS
return_str:string(format:long,ret:long)
ARGUMENTS
format
Variable to determine return type base value
ret
Return value (typically $return)
DESCRIPTION
This function is used by the syscall tapset, and returns a string. Set format equal to 1 for a decimal, 2
for hex, 3 for octal.
Note that this function is preferred over returnstr.
SystemTap Tapset Reference March 2016 FUNCTION::RETURN_STR(3stap)