This section discusses issues to consider when migrating C language programs from VAX systems, HP 9000 Series 300/400, and HP 9000 Series 500 computers to HP workstations and servers. The first section lists some steps you need to take to migrate an application program to an HP 9000 workstation or server. Subsequent sections in This section highlight major differences between various C compilers and suggest how to modify source files to ease migration.

Because C is a highly portable language, if you follow the recommendations given in Programming for Portability , your program should migrate easily. However, if you use system-dependent programming practices, a program that executes successfully on one computer may not execute properly when transferred to a HP 9000 workstation or server. For example, if you use system-specific I/O routines outside of the standard C library, you will have difficulty with portability.

Migrating an Application

1. Test your program on the current system so you have a copy of the results.
2. Use the tar command (see the HP-UX Reference Manual) with the cv options to transfer the source files you want to migrate to tape.
3. Use the tar command with the r option to transfer any associated data files to tape.
4. Install the source files and any related data files on the HP 9000 workstation or server using the tar command with the x option.
5. Check your makefiles for any implementation-specific options. Change programs depending on implementation-specific command options. On HP-UX systems, these options are generally preceded by -W or +, and may include options to be passed to ld or cpp. You can optionally include the -g option to permit symbolic debugging.
6. Review Programming for Portability and Practices to Avoid and check over the source code for system-dependent programming. (If the source files are extensive, you may want to skip this step and catch errors when you run lint or compile.)
7. Search for instances of #include files and make sure that the files or routines included appear in the correct directory or library on the HP 9000 workstation or server.
8. Run lint, a C program checker that verifies source code and prints warning messages about problems with the source code style, efficiency, portability, and consistency.
9. Compile the program on the HP 9000 workstation or server using the cc command. (Refer to the HP C/HP-UX Reference Manual for details about the cc command and options, and explanations of error, warning, and panic messages.) Change the source code to resolve any messages you receive.
10. Recompile the program until you receive no messages.
11. Link the program. The linker reports any symbols that cannot be found.
12. Run the program on the HP 9000 workstation or server. Compare the results with those received on the original computer.

Byte Order

Data Alignment

Unsupported Keywords

Predefined Macro Names

The HP 9000 workstation and server preprocessors predefine the macro names PWB, hpux, and unix. The HP 9000 workstations and servers predefine the macro name hp9000s800; the HP 9000 Series 500 predefines hp9000s500; and the HP 9000 Series 300/400 predefine the macro name hp9000s300. The VAX predefines the macro name vax. If any of these macro names is used as an identifier in the source code, use the #undef preprocessor directive to "undefine" the macro or rename the identifier(s).

In ANSI mode, none of the above macro names are defined and you should not have difficulty with these HP C specific macro names.

White Space

Hexadecimal Escape Sequence

Check your source files for any occurrences for \x, and verify that a hexadecimal escape sequence is intended.

Invalid Structure References

     struct x {
       int y;
     }z;
     char *c;
     c -> y=5;

     c = (char *) &z;
     ((struct x *) c)->y = 5;

Leading Underscore

Library Functions

Typedefs

For example:

     typedef long t;
     unsigned t var;

     typedef unsigned long t;
     t var;

#define t long
     unsigned t var;