File: make.info,  Node: Archive Symbols,  Prev: Archive_Update.php">Archive Update,  Up: Archive_Update.php">Archive Update

11.2.1 Updating Archive Symbol Directories
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An archive file that is used as a library usually contains a special
member named '__.SYMDEF' that contains a directory of the external
symbol names defined by all the other members.  After you update any
other members, you need to update '__.SYMDEF' so that it will summarize
the other members properly.  This is done by running the 'ranlib'
program:

     ranlib ARCHIVEFILE

   Normally you would put this command in the rule for the archive file,
and make all the members of the archive file prerequisites of that rule.
For example,

     libfoo.a: libfoo.a(x.o y.o ...)
             ranlib libfoo.a

The effect of this is to update archive members 'x.o', 'y.o', etc., and
then update the symbol directory member '__.SYMDEF' by running 'ranlib'.
The rules for updating the members are not shown here; most likely you
can omit them and use the implicit rule which copies files into the
archive, as described in the preceding section.

   This is not necessary when using the GNU 'ar' program, which updates
the '__.SYMDEF' member automatically.