[G-2] gs_graphinfo -- Subroutine to obtain information about memory graph
gs_graphinfo returns information, including the command that generated
gs_graphinfo produces no output except for error messages.
gs_graphinfo mirrors gs_fileinfo; see gs_fileinfo.
gs_graphinfo stores the following in r():
local r(fn) graph name
local r(ft) "live"
local r(scheme) scheme name
local r(ysize) ysize() value
local r(xsize) xsize() value
local r(command) command
local r(command_date) date on which command was run
local r(command_time) time at which command was run
local r(family) family to which command belongs
local r(dtafile) .dta file in memory at command_time
local r(dtafile_date) .dta file date
Note that any of r(command), ..., r(dtafile_date) may be undefined, so
refer to contents using macro quoting.