LD(1)							      General Commands Manual							     LD(1)

NAME

       ld - loader

SYNOPSIS

       ld [ option ] file ...

DESCRIPTION

       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  defin-
       ing  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 dictio-
       nary 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 erroneous 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 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.

       -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 defini-
	      tions from being given to common 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 separate 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 a.out.

       -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.

FILES

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

SEE ALSO

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

BUGS

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