11/3/71 LD (I)
NAME ld -- link editor
SYNOPSIS ld [ -usaol ] name ]
1
DESCRIPTION ld combines several object programs into one;
resolves external references; and searches li-
braries. In the simplest case the names of sev-
eral object programs are given, and ld combines
them, producing an object module which can be ei-
ther executed or become the input for a further
ld run.
The argument routines are concatenated in the or-
der specified. The entry point of the output is
the beginning of the first routine.
If any argument is a library, it is searched, and
only those routines defining an unresolved exter-
nal reference are loaded. If any routine loaded
from a library refers to an undefined symbol
which does not become defined by the end of the
library, the library is searched again. Thus the
order of libraries primarily affects the effi-
ciency of loading, not what routines get loaded.
ld understands several flag arguments which are
written preceded by a "-":
-s "squash" the output, that is, remove the
symbol table and relocation bits to save
space (but impair the usefulness of the de-
bugger). This information can also be re-
moved by strip.
-u take the following argument as a symbol and
enter it as undefined in the symbol table.
This is useful for loading wholly from a
library, since initially the symbol table
is empty and an unresolved reference is
needed to force the loading of the first
routine.
-o set the origin of the load to the octal
number which is given as the next argument.
This option affects only the definition of
relocatable external symbols. See DMR be-
fore using.
-l This option is an abbreviation for a li-
brary name. "-l" alone stands for
"/etc/liba.a", which is the standard system
library for assembly language programs.
"-lx" stands for "/etc/libx.a" where x is
any character. There are libraries for
Fortran (x="f") and B (x="b").
-a means "absolute" (load at origin absolute
0) but it doesn't work.
The output of ld is left on a.out. This file is
executable only if no errors occurred during the
load.
FILES /etc/libx.a, for various x;
/etc/ltma, ltmb, ... (temporary)
a.out (output file)
SEE ALSO as, strip, ar (maintains libraries)
DIAGNOSTICS "can't create temp file"-- unwritable directory
or someone else is using ld in the same direc-
tory.
"can't open temp file"-- maybe someone has delet-
ed it out from under you.
"file not found"-- bad argument
"bad format"-- bad argument
"relocation error"-- bad argument (relocation
bits corrupted)
"bad relocation"-- user error: a relocatable
reference to an external symbol that turns out to
be absolute.
"multiply defined"-- same symbol defined twice in
same load
"un"-- stands for "undefined symbol"
"symbol not found"-- loader bug
BUGS Option "-a" doesn't work at all; option "-o"
doesn't work right.
OWNER dmr