hello all! thanks for all the help. I got another problem. :P I use gcc to compile a program running on aix 5.2. but when I copied it into aix 4.3. it won't run I get the error exec(): 0509-036 Cannot load program ./test1 because of the following errors: 0509-023 Symbol ___memset in test1 is not defined. 0509-023 Symbol ___memmove in test1 is not defined. 0509-023 Symbol __malloc_user_defined_name in test1 is not defined. 0509-026 System error: Cannot run a file that does not have a valid format. is there a flag that I missed that I could use when I compile on aix 5 that will allow me to run the program on a lower version of the os? neeeed help!thanks! __________________________________ Do you Yahoo!? Yahoo! SiteBuilder - Free, easy-to-use web site design software http://sitebuilder.yahoo.com