[avr-libc-dev] [bug #50811] using -Wl, -u, vfprintf -lprintf_min causes program to grow a lot

[Joerg Wunsch]

Follow-up Comment #6, bug #50811 (project avr-libc):

Well, the fact that the -u vfprintf needs to be forced is
an unfortunate side effect of libprintf_min.a *only* containing
a different definition of vfprintf(), but not e.g. for printf()
or other members of the family.

Thus, if you only add -lprintf_min, this library will be
processed by a time when the linker has not seen any obvious
need to drag the vfprintf symbol in from it, so in effect, it
will be ignored.  Later on, when it comes to resolve the
symbols needed by (e.g.) printf, it will suddenly also need
vfprintf, but libprintf_min.a is already done by that time,
so the standard version of vfprintf is used (from libc.a).

We could probably reorganize these libraries to also contain
the other printf family members, but 1) that needs to be done
by someone (who?), and 2) it won't fix the history, so the
documentation has to remain the way it is for at least a
while (a couple of years or more).

While the complaint this bug is focussing on is not
completely invalid, I think it's practically a non-issue:
except for the degraded testcase, nobody would want to drag
in the full power (and bloat) of printf() & co. if all he
wants to do is printing some constant strings without using
any of the formatting functionality.  As soon as a real
printf functionality is needed, as seen, there is indeed a
minimal saving of space by libprintf_min.a.

    _______________________________________________________

Reply to this item at:

  <http://savannah.nongnu.org/bugs/?50811>

_______________________________________________
  Message sent via/by Savannah
  http://savannah.nongnu.org/