ld

【ld - linker】

NAME

     ld -- linker

SYNOPSIS

     ld files...  [options] [-o outputfile]

DESCRIPTION

     The ld command combines several object files and libraries, resolves references, and produces an

     ouput file.  ld can produce a final linked image (executable, dylib, or bundle), or with the -r

     option, produce another object file.  If the -o option is not used, the output file produced is

     named "a.out". 

   Universal

　　     The linker accepts universal (multiple-architecture) input files, but always creates a "thin"

     (single-architecture), standard Mach-O output file.  The architecture for the output file is spec-

     ified using the -arch option.  If this option is not used, ld attempts to determine the output

     architecture by examining the object files in command line order.  The first "thin" architecture

     determines that of the output file.  If no input object file is a "thin" file, the native 32-bit

     architecture for the host is used.

　　     Usually, ld is not used directly.  Instead the gcc(1) compiler driver invokes ld. The compiler

     driver can be passed multiple -arch options and it will create a universal final linked image by

     invoking ld multiple times and then running lipo(1) merge the outputs into a universal file.

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