system_variable

<< [(key word)] system_variable result >> or
<< [(key word) value] system_variable result >>
<< [(key word) optional arg] system_variable result >>
The primitive returns the value of a given system constant.
The primitive sets the value of a given system constant.
PrintDollar [0,1,2], Wrap, P, N, NN, M, MM, L, LL, C, CC,ringName,
CurrentRingp, Verbose, UseCriterion1, UseCriterion2B,
ReduceLowerTerms, CheckHomogenization, Homogenize, Sugar, Homogenize_vec,
Statistics, StackPointer, StandardOperandStack,
ErrorStack, ErrorMessageMode, WarningMessageMode,
CatchCtrlC, Strict, CurrentContextp, NullContextp, Strict2,
SigIgn, KSPushEnvMode, PrimitiveContextp, KanGBmessage,
orderMatrix, gbListTower, Schreyer, 
outputOrder, multSymbol, variableNames, Version,
AvoidTheSameRing, RingStack, LeftBracket, RightBracket,
AutoReduce, SecureMode
Example: [(N)] system_variable
                             (maximum number of variables)/2.
         [(x) (var) 3] system_variable
                              The 3rd variable.
         [(D) (var) 4] system_variable
                              The 4th differential operator.
         [(PrintDollar) 0] system_variable
                          Set the global variable PrintDollar to 0