X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ian/git?a=blobdiff_plain;f=secnet.h;h=d9bd400f95f200105f630498470018ce38bd3cbb;hb=cf423c1b3196e98b0e2abaf56165baf65b6975d9;hp=cd2ea51e9212b96d1886d8ee158b052faf183a3b;hpb=b322d6cbd4fa140338d2f7af47ada689401a14e3;p=secnet.git

diff --git a/secnet.h b/secnet.h
index cd2ea51..d9bd400 100644
--- a/secnet.h
+++ b/secnet.h
@@ -13,6 +13,7 @@
 #include <assert.h>
 #include <fcntl.h>
 #include <unistd.h>
+#include <errno.h>
 #include <sys/poll.h>
 #include <sys/types.h>
 #include <sys/time.h>
@@ -200,6 +201,16 @@ typedef int beforepoll_fn(void *st, struct pollfd *fds, int *nfds_io,
 			  int *timeout_io);
 typedef void afterpoll_fn(void *st, struct pollfd *fds, int nfds);
 
+/* void BEFOREPOLL_WANT_FDS(int want);
+ *   Expects: int *nfds_io;
+ *   Can perform non-local exit.
+ * Checks whether there is space for want fds.  If so, sets *nfds_io.
+ * If not, sets *nfds_io and returns. */
+#define BEFOREPOLL_WANT_FDS(want) do{				\
+    if (*nfds_io<(want)) { *nfds_io=(want); return ERANGE; }	\
+    *nfds_io=(want);						\
+  }while(0)
+
 /* Register interest in the main loop of the program. Before a call
    to poll() your supplied beforepoll function will be called. After
    the call to poll() the supplied afterpoll function will be called.