Hi all, I have successfully build Ruby 1.5.3 under Tru64 with native compiler. > uname -a OSF1 slbhdg V4.0 1229 alpha > cc -V Digital UNIX Compiler Driver 3.11 DEC C V5.9-005 on Digital UNIX V4.0 (Rev. 1229) But I have to change the line CFLAGS = -g to CFLAGS = -oldc -std -g After this, the interpreter could be build (issuing many many warnings). The testsuit runs successful afterwards. Could the flags be considered in future? I have to admit, that this is not Ruby's fault alone. It was resulting from a combination of Ruby's old K&R-C coding style, the system header files partially in ANSI-C and the native compiler which got confused by all of these. :-) Thanks, \cle.