NMEDIT(1)						      General Commands Manual							 NMEDIT(1)

NAME

       nmedit - change global symbols to local symbols

SYNOPSIS

       nmedit -s list_file [-R list_file] [-p] [-A] [-] [[-arch arch_type] ...] object_file ... [-o output]

DESCRIPTION

       Nmedit  changes	the  global  symbols not listed in the list_file file of the -s list_file option to static symbols.  Undefined symbols and
       common symbols are not affected and shouldn't be listed in list_file.  For dynamic libraries symbols are turned into private extern symbols
       that  are  no  longer  external (rather than static symbols).  This is done so that the references between modules of a dynamic library are
       resolved to the symbols in the dynamic library.	Nmedit differs from strip(1) in that it also changes the  symbolic  debugging  information
       (produce by the -g option to cc(1)) for the global symbols it changes to static symbols so that the resulting object can still be used with
       the debugger.

       Nmedit like strip(1) is useful to limit the symbols for use with later linking.	This allows control of the interface that  the	executable
       wants  to provide to the objects that it will dynamically load, and it will not have to publish symbols that are not part of its interface.
       For example an executable that wishes to allow only a subset of its global symbols but all of the shared libraries globals to be used would
       have its symbol table edited with:
	      % nmedit -s interface_symbols -A executable
       where  the file interface_symbols would contain only those symbols from the executable that it wishes the objects loaded at runtime to have
       access to.  Another example is an object that is made up of a number of other objects that will be loaded into an  executable  would  built
       and then have its symbol table edited with:
	      % ld -o relocatable.o -r a.o b.o c.o
	      % nmedit -s interface_symbols relocatable.o
       which  would  leave  only  the symbols listed in the file interface_symbols (and the undefined and common symbols) as global symbols in the
       object file.

       The one or more of the following options is required to nmedit(1) is:

       -s filename
	      Leave the symbol table entries for the global symbols listed in filename global but turn all other global symbols (except  undefined
	      and common symbols) into static symbols.	The symbol names listed in filename must be one per line. Leading and trailing white space
	      are not part of the symbol name.	Lines starting with # are ignored, as are lines with only white space.

       -R filename
	      Change the symbol table entries for the global symbols listed in filename into static symbols.  This file has the same format as the
	      -s filename option above.  If the -R filename option is specified without the -s filename option, then all symbols not listed in the
	      -R filename option's filename are left as globals.  If both a -R filename and a -s filename are given the symbols listed in  the	-R
	      filename are basically ignored and only those symbols listed in the -s filename are saved.

       -p     Change  symbols  to  private  externs instead of static.	This is allowed as the only option to change all defined global symbols to
	      private externs.

       The options to nmedit(1) are:

       -A     Leave all global absolute symbols except those with a value of zero, and	save  objective-C  class  symbols  as  globals.   This	is
	      intended for use of programs that load code at runtime and want the loaded code to use symbols from the shared libraries.

       -      Treat all remaining arguments as file names and not options.

       -arch arch_type
	      Specifies  the  architecture, arch_type, of the file for nmedit(1) to process when the file is a universal file (see arch(3) for the
	      currently know arch_types).  The arch_type can be all to process all architectures in the file.	The  default  is  to  process  all
	      architectures that are contained in the file.

       -o output
	      Write the result into the file output.

SEE ALSO

       strip(1), ld(1), arch(3)

BUGS

       The  changing of the symbolic debugging information by nmedit is not known to be totally correct and could cause the debugger to crash, get
       confused or produce incorrect information.

Apple Inc.							   May 29, 2007 							 NMEDIT(1)