everest% CC -c astring3.C
"astring3.h", line 20: error(1077): this declaration has no storage class
or
          type specifier
     mutable int length ;
     ^

"astring3.h", line 20: error(1065): expected a ";"
     mutable int length ;
             ^

"astring3.C", line 13: error(1020): identifier "length" is undefined
     length = -1 ;
     ^

"astring3.C", line 17: error(1020): identifier "length" is undefined
     length = -1 ;
     ^

"astring3.C", line 32: error(1020): identifier "length" is undefined
     length = -1 ;
     ^

"astring3.C", line 47: error(1020): identifier "length" is undefined
     if (length >= 0) return length ;
         ^

6 errors detected in the compilation of "astring3.C".
everest% 


everest% g++ -c astring3.C
everest%