3/15/72 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. In the latter case, the "-r" option must
be given to preserve the relocation bits.
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 ex-
actly once. Only those routines defining an un-
resolved external reference are loaded. If a
routine from a library references another routine
in the library, the referenced routine must ap-
pear after the referencing routine in the li-
brary. Thus the order of libraries is important.
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.
-l This option is an abbreviation for a li-
brary name. "-l" alone stands for
"/usr/lib/liba.a", which is the standard
system library for assembly language pro-
grams. "-lx" stands for "/usr/lib/libx.a"
where x is any character. There are li-
braries for Fortran (x="f"), C (x="c"), Ex-
plor (x="e") and B (x="b").
-x Do not preserve local (non-.globl) symbols
in the output symbol table; only enter ex-
ternal symbols. This option saves some
space in the output file.
-r generate relocation bits in the output file
so that it can be the subject of another ld
run.
The output of ld is left on a.out. This file is
executable only if no errors occurred during the
load.
FILES /usr/lib/lib?.a libraries
a.out output file
SEE ALSO as(I), ar(I)
DIAGNOSTICS "file not found"-- bad argument
"bad format"-- bad argument
"relocation error"-- bad argument (relocation
bits corrupted)
"multiply defined"-- same symbol defined twice in
same load
"un"-- stands for "undefined symbol"
"symbol not found"-- loader bug
"can't move output file"-- can't move temporary
to a.out file
"no relocation bits"-- an input file lacks relo-
cation information
"too many symbols"-- too many references to ex-
ternal symbols in a given routine
"premature EOF"
"can't create l.out"-- cannot make temporary file
"multiple entry point"-- more than one entry
point specified (not possible yet).
BUGS Instructions in the data segment are not relo-
cated properly.
OWNER dmr