I, too, prefer the doc, but you can also write a program to experiment/validate. Here is a program that makes a string of length N and puts it into a macro variable (which also has a maximum length). If you use this value in the LABEL statement to set a variable label, you can see whether it works for 257 length:
%let N = 257;
data _NULL_;
length L $&N;
L = subpad("A",1,257);
call symput("lbl", L);
run;
data Want;
label A = "&lbl";
a = 1;
run;
For this program, you get the following WARNING:
WARNING: Label value for variable A has been truncated to a length of 256 bytes.
... View more
