diff --git a/src/scanner.c b/src/scanner.c
index 809130b1..b6b8d250 100644
--- a/src/scanner.c
+++ b/src/scanner.c
@@ -404,11 +404,13 @@ start_element(void *data, const char *element_name, const char **atts)
 			message->destructor = 0;
 
 		if (since != NULL) {
+			int prev_errno = errno;
 			errno = 0;
 			version = strtol(since, &end, 0);
-			if (errno == EINVAL || end == since || *end != '\0')
+			if (errno != 0 || end == since || *end != '\0')
 				fail(&ctx->loc,
 				     "invalid integer (%s)\n", since);
+			errno = prev_errno;
 		} else {
 			version = 1;
 		}
diff --git a/src/wayland-client.c b/src/wayland-client.c
index b0f77b9e..01629e01 100644
--- a/src/wayland-client.c
+++ b/src/wayland-client.c
@@ -829,9 +829,12 @@ wl_display_connect(const char *name)
 
 	connection = getenv("WAYLAND_SOCKET");
 	if (connection) {
+		int prev_errno = errno;
+		errno = 0;
 		fd = strtol(connection, &end, 0);
-		if (*end != '\0')
+		if (errno != 0 || connection == end || *end != '\0')
 			return NULL;
+		errno = prev_errno;
 
 		flags = fcntl(fd, F_GETFD);
 		if (flags != -1)