diff --git a/libguile/poll.c b/libguile/poll.c
index d61d51979..1bb75727b 100644
--- a/libguile/poll.c
+++ b/libguile/poll.c
@@ -184,6 +184,7 @@ scm_init_poll (void)
 {
 #if HAVE_POLL
   scm_c_define_gsubr ("primitive-poll", 4, 0, 0, scm_primitive_poll);
+  scm_c_define ("%sizeof-struct-pollfd", scm_from_size_t (sizeof (struct pollfd)));
 #else
   scm_misc_error ("%init-poll", "`poll' unavailable on this platform", SCM_EOL);
 #endif
diff --git a/module/ice-9/poll.scm b/module/ice-9/poll.scm
index cf61294d7..2ba868748 100644
--- a/module/ice-9/poll.scm
+++ b/module/ice-9/poll.scm
@@ -38,6 +38,9 @@
   (load-extension (string-append "libguile-" (effective-version))
                   "scm_init_poll"))
 
+(if (not (= %sizeof-struct-pollfd 8))
+    (error "Unexpected struct pollfd size" %sizeof-struct-pollfd))
+
 (if (defined? 'POLLIN)
     (export POLLIN))