Re: Very basic question: How to use gnatmake (not gprbuild) using external libraries?

[Kenneth Wolcott <kennethwolcott@gmail.com>]

On Wednesday, June 28, 2023 at 12:02:16 PM UTC-7, Jeffrey R.Carter wrote:
> On 2023-06-28 20:25, Kenneth Wolcott wrote: 
> > On Wednesday, June 28, 2023 at 12:20:09 AM UTC-7, Jeffrey R.Carter wrote: 
> >> On 2023-06-28 01:44, Kenneth Wolcott wrote: 
> >>> 
> >>> 1. Where do I place the SDL library from GitHub? 
> >> That is up to you. It goes in /path/to/SDL/, where you choose /path/to/. 
> > 
> > Cool.
> I probably should have mentioned that the library build procedure may expect a 
> specific directory structure under /path/to/SDL/, and failure to create/keep 
> that may result in the build process failing.
> > I'm not sure I understand the distinction between "-I/path" and "-L/path". I think when one includes ("-I/path") something it will be compiled along with what I'm trying to compile and when I use "-L/path" it means use *.obj, *.ali, etc at the linking stage. Is that correct?
> From the GNAT user guide 
> (https://docs.adacore.com/live/wave/gnat_ugn/html/gnat_ugn/gnat_ugn/building_executable_programs_with_gnat.html#switches-for-gnatmake), 
> -I/path/ is equivalent to -aO/path/ -aI/path/. -aO/path/ says to look for 
> library and object files (.ali & .o) in /path/ in addition to the current 
> directory. -aI/path/ says to look for source files in /path/ in addition to the 
> current directory. 
> 
> -L/path/ is equivalent to -largs -L/path/, so it's a linker switch. 
> 
> I should probably have mentioned that it's probably a good idea to write-protect 
> the library's .ali files one the library is built. This prevents other 
> compilations from recompiling the library. 
> 
> In my experience, if you have the library's source, .ali, and .o files in 
> /path/, then -I/path/ is all you need to compile and link against the library.

Thank you for the clarification/elaboration.

Ken