and such a PCH file won't work.
@end deftypefn
+@deftypefn {Host Hook} size_t HOST_HOOKS_GT_PCH_ALLOC_GRANULARITY (void);
+This host hook returns the alignment required for allocating virtual
+memory. Usually this is the same as getpagesize, but on some hosts the
+alignment for reserving memory differs from the pagesize for committing
+memory.
+@end deftypefn
+
@node Filesystem
@section Host Filesystem
@cindex configuration file