Hello there,
I need to know if is there any option to compile a delphi project only if the source or any used unit, package etc has been changed.
If this is not possible, second alternative : Is there any option to generate exactly the same binary compiling two times the same project.
Thanks.
Edit: The usage is for a hash based WebUpdate.
Delphi compiles only changed units on a compile, and compiles all units regardless of change-status on a build.
Exe's are never the same, on a binary level. Just built a project twice, renamed the exe's to have a txt extension and compared them with Beyond Compare: it shows differences.
A Delphi "compile" will compile only changed units. But as said, unit have data so the compiler can check which needs updating and which not. And the executable can change because the build process can rearrange the exe. Your web updates should not use a file hash, it should use version information to decide what to update and what not. That's the way installers check which files should be replaced.
One (hard) solution: Make your exes using a Makefile! A makefile allows you to say "this exe is made from those files, using those commands". Make will only run "those commands" if at least one of the files you list as making up your exe is newer then your exe.
The hard part in this is setting up the list of files that make up your exe: You can easily get the list of files listed in the DPR/DPROJ, but you'll also need to identify all the linked resources ($R), all the included files ($INCLUDE), all the files that are implictelly compiled by Delphi because they're used in the "uses" clauses and are found on the Library Path.
Generating a Makefile for the general case is very difficult, but for one particular project it might work. For example you might consider your file dependent on only the files listed in the DPR files and then make sure you add all the relevant files to the DPR.