31 Dec
2018
31 Dec
'18
12:56 a.m.
On Sun, Dec 30, 2018, 1:49 PM <ron(a)ronnatalie.com wrote:
Yes, it pretty much has to be this way as it is a
single pass process and
the ar format is simple.
The later libraries have a symbol "dictionary" added to the beginning.
Before that you manually arranged the order of the relocatables in the
library and later automated tools to put them in dependency order (ranlib,
etc...) came about.
Tsort/lorder put them in dependency order. Ranlib gave the index of symbols
as the first or last archive member... in time, the indexing moved up into
ar....
Warner
-----Original
Message-----
From: TUHS <tuhs-bounces(a)minnie.tuhs.org> On Behalf Of Paul Winalski
Sent: Sunday, December 30, 2018 1:34 PM
To: Noel Chiappa <jnc(a)mercury.lcs.mit.edu>
Cc: tuhs(a)minnie.tuhs.org
Subject: Re: [TUHS] Deleted lib1 and lib2 in v6, recoverable?
On 12/28/18, Noel Chiappa <jnc(a)mercury.lcs.mit.edu> wrote:
all OSes
If so, the thing is that the V6 linker won't pull in an object module
from a library unless a global in it satisfies an already existing
(i.e. in the linking process) undefined global. (I don't know if this
is true of later linkers; never used 'em.)
I think this has been pretty much universal behavior for all linkers on since the 1960s. It continues to be true today.
Sometimes one runs into a situation where a module loaded from lib1.a has
an undefined symbol that causes a module from lib2.a to be loaded, and
that
module in turn has an undefined symbol that is
defined in lib1.a. In
that
case, you have to cause the linker to scan
lib1.a
twice:
ld main.o lib1.a lib2.a lib1.a
-Paul W.