screenshot: Print warning if we're not launched from weston
weston-screenshooter is a helper binary that weston launches to write the
screenshot to disk. If somebody tries to launch it by hand, print a
warning and mention the screenshot keybinding.
diff --git a/clients/screenshot.c b/clients/screenshot.c
index efacfed..1f73df6 100644
--- a/clients/screenshot.c
+++ b/clients/screenshot.c
@@ -248,6 +248,13 @@
struct screenshooter_output *output;
int width, height;
+ if (getenv("WAYLAND_SOCKET") == NULL) {
+ fprintf(stderr, "%s is must be launched by weston.\n"
+ "Use the MOD+S shortcut to take a screenshot.",
+ argv[0]);
+ return -1;
+ }
+
display = wl_display_connect(NULL);
if (display == NULL) {
fprintf(stderr, "failed to create display: %m\n");