2 files changed, 9 insertions, 2 deletions
diff --git a/src/basic/terminal-util.c b/src/basic/terminal-util.c
index 8ded46f493..4172db12a5 100644
--- a/src/basic/terminal-util.c
+++ b/src/basic/terminal-util.c
@@ -1923,12 +1923,12 @@ int get_default_background_color(double *ret_red, double *ret_green, double *ret
         if (tcsetattr(STDIN_FILENO, TCSADRAIN, &new_termios) < 0)
                 return -errno;
 
-        r = loop_write(STDOUT_FILENO, "\x1B]11;?\x07", SIZE_MAX);
+        r = loop_write(STDOUT_FILENO, "\x1B]11;?" ANSI_ST, SIZE_MAX);
         if (r < 0)
                 goto finish;
 
         usec_t end = usec_add(now(CLOCK_MONOTONIC), 333 * USEC_PER_MSEC);
-        char buf[STRLEN("\x1B]11;rgb:0/0/0\x07")]; /* shortest possible reply */
+        char buf[STRLEN("\x1B]11;rgb:0/0/0" ANSI_ST)]; /* shortest possible reply */
         size_t buf_full = 0;
         BackgroundColorContext context = {};
 
diff --git a/src/basic/terminal-util.h b/src/basic/terminal-util.h
index b446e547d6..3d02e92d0b 100644
--- a/src/basic/terminal-util.h
+++ b/src/basic/terminal-util.h
@@ -27,6 +27,13 @@
 #define ANSI_WINDOW_TITLE_PUSH "\x1b[22;2t"
 #define ANSI_WINDOW_TITLE_POP "\x1b[23;2t"
 
+/* ANSI "string terminator" character ("ST"). Terminal emulators typically allow three different ones: 0x07,
+ * 0x9c, and 0x1B 0x5C. We'll avoid 0x07 (BEL, aka ^G) since it might trigger unexpected TTY signal
+ * handling. And we'll avoid 0x9c since that's also valid regular codepoint in UTF-8 and elsewhere, and
+ * creates ambiguities. Because of that some terminal emulators explicitly choose not to support it. Hence we
+ * use 0x1B 0x5c */
+#define ANSI_ST "\e\\"
+
 bool isatty_safe(int fd);
 
 int terminal_reset_defensive(int fd, bool switch_to_text);