So the non-portable MSG_DONTWAIT may alleviate the problem... might

as well use it on architectures that support it.

2 files changed, 19 insertions, 2 deletions

diff --git a/src/sysdeps/trymsgdontwait.c b/src/sysdeps/trymsgdontwait.c
new file mode 100644
index 0000000..0c8ad15
--- /dev/null
+++ b/src/sysdeps/trymsgdontwait.c
@@ -0,0 +1,17 @@
+/* ISC license. */
+
+#undef _POSIX_C_SOURCE
+#undef _XOPEN_SOURCE
+
+#ifndef _XPG4_2
+# define _XPG4_2
+#endif
+
+#ifndef _BSD_SOURCE
+#define _BSD_SOURCE
+#endif
+
+#include <sys/types.h>
+#include <sys/socket.h>
+
+int value = MSG_DONTWAIT ;
diff --git a/src/sysdeps/tryokwaitall.c b/src/sysdeps/trynbwaitall.c
index 15721b5..0f55080 100644
--- a/src/sysdeps/tryokwaitall.c
+++ b/src/sysdeps/trynbwaitall.c
@@ -53,8 +53,8 @@ static int child (int p, int fd)
   if (write(p, "", 1) < 1) return 111 ; /* sync with the parent */
   if (select(fd+1, &rfds, 0, 0, 0) < 1) return 111 ;
 
-  /* On buggy systems, the following recvmsg will block, despite
-     setting the fd non-blocking */
+  /* The following recvmsg may block, despite setting the fd
+     non-blocking. That is what we're testing. */
 
   if (recvmsg(fd, &msg, MSG_WAITALL) < 1) return 111 ;
   if (write(p, "", 1) < 1) return 111 ;