diff --git a/qemu-sockets.c b/qemu-sockets.c
index c526324998b07047daec34b209707e2f817d3935..eda1850e9c6a02a1ae52af465c78fc31bf7e9573 100644
--- a/qemu-sockets.c
+++ b/qemu-sockets.c
@@ -627,24 +627,28 @@ int unix_connect(const char *path)
 int unix_listen_opts(QemuOpts *opts)
 {
     fprintf(stderr, "unix sockets are not available on windows\n");
+    errno = ENOTSUP;
     return -1;
 }
 
 int unix_connect_opts(QemuOpts *opts)
 {
     fprintf(stderr, "unix sockets are not available on windows\n");
+    errno = ENOTSUP;
     return -1;
 }
 
 int unix_listen(const char *path, char *ostr, int olen)
 {
     fprintf(stderr, "unix sockets are not available on windows\n");
+    errno = ENOTSUP;
     return -1;
 }
 
 int unix_connect(const char *path)
 {
     fprintf(stderr, "unix sockets are not available on windows\n");
+    errno = ENOTSUP;
     return -1;
 }