@example
/* @r{Use prototypes unless the compiler is old-fashioned.} */
-#if __STDC__
+#ifdef __STDC__
#define P(x) x
#else
#define P(x) ()
@end smallexample
@noindent
-force the compiler to insure (as fas as it can) that each variable whose
+force the compiler to insure (as far as it can) that each variable whose
type is @code{struct S} or @code{more_aligned_int} will be allocated and
aligned @emph{at least} on a 8-byte boundary. On a Sparc, having all
variables of type @code{struct S} aligned to 8-byte boundaries allows
return waitpid (-1, p.__ip, 0);
@}
@end example
+
+@item unused
+When attached to a type (including a @code{union} or a @code{struct}),
+this attribute means that variables of that type are meant to appear
+possibly unused. GNU CC will not produce a warning for any variables of
+that type, even if the variable appears to do nothing. This is often
+the case with lock or thread classes, which are usually defined and then
+not referenced, but contain constructors and destructors that have
+non-trivial bookeeping functions.
+
@end table
To specify multiple attributes, separate them by commas within the
@enumerate
@item
+Compile your template-using code with @samp{-frepo}. The compiler will
+generate files with the extension @samp{.rpo} listing all of the
+template instantiations used in the corresponding object files which
+could be instantiated there; the link wrapper, @samp{collect2}, will
+then update the @samp{.rpo} files to tell the compiler where to place
+those instantiations and rebuild any affected object files. The
+link-time overhead is negligible after the first pass, as the compiler
+will continue to place the instantiations in the same files.
+
+This is your best option for application code written for the Borland
+model, as it will just work. Code written for the Cfront model will
+need to be modified so that the template definitions are available at
+one or more points of instantiation; usually this is as simple as adding
+@code{#include <tmethods.cc>} to the end of each template header.
+
+For library code, if you want the library to provide all of the template
+instantiations it needs, just try to link all of its object files
+together; the link will fail, but cause the instantiations to be
+generated as a side effect. Be warned, however, that this may cause
+conflicts if multiple libraries try to provide the same instantiations.
+For greater control, use explicit instantiation as described in the next
+option.
+
+@item
Compile your code with @samp{-fno-implicit-templates} to disable the
implicit generation of template instances, and explicitly instantiate
all the ones you use. This approach requires more knowledge of exactly