[Fedora-packaging] When to use a leading underscore?
As maintainer of fedora-gnat-project-common I sometimes work on RPM macros for
use in Ada packages. Every time I define a new macro I have trouble deciding
whether its name should begin with an underscore or not. I know that there is
some technical difference but I've never quite understood what practical
difference it makes.
I've been trying to imitate macros with a similar function, so I defined
_GNAT_project_dir with a leading underscore in analogy with _libdir and
others. Macros containing command line flags for build tools I've defined
without a leading underscore in analogy with optflags, but then there are
_smp_mflags and the hardening macros which have the underscore, and
__global_cflags and __global_ldflags even have two leading underscores.
Could someone explain what difference a leading underscore makes and give some
guidance on when I should use it?
Is a double leading underscore functionally different from a single one, or is
that just some kind of naming convention?
Björn Persson