--- lbbs/src/str_process.c	2025/11/08 08:21:31	1.28
+++ lbbs/src/str_process.c	2026/01/03 10:27:14	1.35
@@ -3,9 +3,13 @@
  * str_process
  *   - common string processing features with UTF-8 support
  *
- * Copyright (C) 2004-2025  Leaflet <leaflet@leafok.com>
+ * Copyright (C) 2004-2026  Leaflet <leaflet@leafok.com>
  */
 
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
 #include "common.h"
 #include "log.h"
 #include "str_process.h"
@@ -38,14 +42,14 @@ int str_length(const char *str, int skip
 
 		if (skip_ctrl_seq && c == '\033' && str[i + 1] == '[') // Skip control sequence
 		{
-			for (i = i + 2; isdigit(str[i]) || str[i] == ';' || str[i] == '?'; i++)
+			for (i = i + 2; isdigit((int)str[i]) || str[i] == ';' || str[i] == '?'; i++)
 				;
 
 			if (str[i] == 'm') // valid
 			{
 				// skip
 			}
-			else if (isalpha(str[i]))
+			else if (isalpha((int)str[i]))
 			{
 				// unsupported ANSI CSI command
 			}
@@ -72,9 +76,13 @@ int str_length(const char *str, int skip
 
 			if (mbstowcs(wcs, input_str, 1) == (size_t)-1)
 			{
-				log_error("mbstowcs(%s) error\n", input_str);
+				log_debug("mbstowcs(%s) error", input_str);
+				wc_len = (UTF8_fixed_width ? 2 : 1); // Fallback
+			}
+			else
+			{
+				wc_len = (UTF8_fixed_width ? 2 : wcwidth(wcs[0]));
 			}
-			wc_len = (UTF8_fixed_width ? 2 : wcwidth(wcs[0]));
 
 			i += (str_len - 1);
 			ret += wc_len;
@@ -132,9 +140,14 @@ int split_line(const char *buffer, int m
 
 			if (mbstowcs(wcs, input_str, 1) == (size_t)-1)
 			{
-				log_error("mbstowcs(%s) error\n", input_str);
+				log_debug("mbstowcs(%s) error", input_str);
+				wc_len = (UTF8_fixed_width ? 2 : 1); // Fallback
 			}
-			wc_len = (UTF8_fixed_width ? 2 : wcwidth(wcs[0]));
+			else
+			{
+				wc_len = (UTF8_fixed_width ? 2 : wcwidth(wcs[0]));
+			}
+
 			if (*p_display_len + wc_len > max_display_len)
 			{
 				break;
@@ -186,7 +199,7 @@ long split_data_lines(const char *p_buf,
 		// Exceed max_line_cnt
 		if (line_cnt + 1 >= line_offsets_count)
 		{
-			// log_error("Line count %d reaches limit %d\n", line_cnt + 1, line_offsets_count);
+			log_debug("Line count %d reaches limit %d", line_cnt + 1, line_offsets_count);
 			return line_cnt;
 		}