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LD(1)											    LD(1)

       ld - loader

       ld [ option ] file ...

       Ld  combines  several object programs into one, resolves external references, and searches
       libraries.  In the simplest case several object files are given,  and  ld  combines  them,
       producing  an object module which can be either 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 output of ld is left on a.out.  This file is made executable only if no errors
       occurred during the load.

       The argument routines are concatenated in the order specified.  The  entry  point  of  the
       output is the beginning of the first routine.

       If  any	argument is a library, it is searched exactly once at the point it is encountered
       in the argument list.  Only those routines defining an unresolved external  reference  are
       loaded.	 If  a	routine from a library references another routine in the library, and the
       library has not been processed by ranlib(1), the referenced routine must appear after  the
       referencing  routine  in  the library.  Thus the order of programs within libraries may be
       important.  If the first member of a library is named `__.SYMDEF', then it  is  understood
       to  be a dictionary for the library such as produced by ranlib; the dictionary is searched
       iteratively to satisfy as many references as possible.

       The symbols `_etext', `_edata' and `_end' (`etext', `edata' and `end' in C) are	reserved,
       and  if	referred  to, are set to the first location above the program, the first location
       above initialized data, and the first location above all data respectively.  It	is  erro-
       neous to define these symbols.

       Ld understands several options.	Except for -l, they should appear before the file names.

       -s     `Strip'  the  output,  that is, remove the symbol table and relocation bits to save
	      space (but impair the usefulness of the debugger).  This information  can  also  be
	      removed by strip(1).

       -u     Take the following argument as a symbol and enter it as undefined in the symbol ta-
	      ble.  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.

       -lx    This option is an abbreviation for the library name `/lib/libx.a',  where  x  is	a
	      string.  If that does not exist, ld tries `/usr/lib/libx.a'.  A library is searched
	      when its name is encountered, so the placement of a -l is significant.

       -x     Do not preserve local (non-.globl) symbols in the output symbol table;  only  enter
	      external symbols.  This option saves some space in the output file.

       -X     Save  local  symbols  except  for those whose names begin with `L'.  This option is
	      used by cc(1) to discard internally generated labels while retaining symbols  local
	      to routines.

       -r     Generate	relocation  bits  in  the  output  file  so that it can be the subject of
	      another ld run.  This flag also prevents final definitions from being given to com-
	      mon symbols, and suppresses the `undefined symbol' diagnostics.

       -d     Force definition of common storage even if the -r flag is present.

       -n     Arrange  that  when the output file is executed, the text portion will be read-only
	      and shared among all users executing the file.  This involves moving the data areas
	      up to the first possible 4K word boundary following the end of the text.

       -i     When the output file is executed, the program text and data areas will live in sep-
	      arate address spaces.  The only difference between this option and -n is that  here
	      the data starts at location 0.

       -o     The  name  argument  after -o is used as the name of the ld output file, instead of

       -e     The following argument is taken to be the name of the entry  point  of  the  loaded
	      program; location 0 is the default.

       -O     This is an overlay file, only the text segment will be replaced by exec(2).  Shared
	      data must have the same layout as in the program overlaid.

       -D     The next argument is a decimal number that sets the size of the data segment.

       /lib/lib*.a	libraries
       /usr/lib/lib*.a	more libraries
       a.out		output file

       as(1), ar(1), cc(1), ranlib(1)

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