Revert using wchar_t functions (9cf94d5 + 2eaf5b0). Big mistake, wchar_t is not guaranteed to be 16-bits.

docs/CHANGELOG.txt

@@ -59,7 +59,7 @@ Other Changes:
   introduced in 1.50 and broken in 1.60. (#1698, #894, #713).
 - TextUnformatted(): Fixed a case where large-text path would read bytes past the text_end marker depending
   on the position of new lines in the buffer (it wasn't affecting the output but still not the right thing to do!) 
-- InputTextMultiline(), RenderText(): Some optimization for very large text buffers, useful for non-optimized builds.
+- RenderText(): Some optimization for very large text buffers, useful for non-optimized builds.
 - BeginMenu(): Fixed menu popup horizontal offset being off the item in the menu bar when WindowPadding=0.0f.
 - ArrowButton(): Fixed arrow shape being horizontally misaligned by (FramePadding.y-FramePadding.x) if they are different.
 - Drag and Drop: Added GetDragDropPayload() to peek directly into the payload (if any) from anywhere. (#143)

imgui.cpp

@@ -850,7 +850,6 @@ CODE
 
 #include <ctype.h>      // toupper, isprint
 #include <stdio.h>      // vsnprintf, sscanf, printf
-#include <wchar.h>      // wcslen
 #if defined(_MSC_VER) && _MSC_VER <= 1500 // MSVC 2008 or earlier
 #include <stddef.h>     // intptr_t
 #else
@@ -1220,7 +1219,10 @@ const char* ImStrchrRange(const char* str, const char* str_end, char c)
 
 int ImStrlenW(const ImWchar* str)
 {
-    return (int)wcslen((const wchar_t*)str);
+    //return (int)wcslen((const wchar_t*)str);	// FIXME-OPT: Could use this when wchar_t are 16-bits
+    int n = 0;
+    while (*str++) n++;
+    return n;
 }
 
 // Find end-of-line. Return pointer will point to either first \n, either str_end.

imgui_widgets.cpp

@@ -36,7 +36,6 @@ Index of this file:
 #include "imgui_internal.h"
 
 #include <ctype.h>      // toupper, isprint
-#include <wchar.h>      // wmemchr
 #if defined(_MSC_VER) && _MSC_VER <= 1500 // MSVC 2008 or earlier
 #include <stddef.h>     // intptr_t
 #else
@@ -3618,7 +3617,9 @@ bool ImGui::InputTextEx(const char* label, char* buf, int buf_size, const ImVec2
             // In multi-line mode, we never exit the loop until all lines are counted, so add one extra to the searches_remaining counter.
             searches_remaining += is_multiline ? 1 : 0;
             int line_count = 0;
-            for (const ImWchar* s = text_begin; (s = (const ImWchar*)wcschr((const wchar_t*)s, (wchar_t)'\n')) != NULL; s++)
+            //for (const ImWchar* s = text_begin; (s = (const ImWchar*)wcschr((const wchar_t*)s, (wchar_t)'\n')) != NULL; s++)  // FIXME-OPT: Could use this when wchar_t are 16-bits
+            for (const ImWchar* s = text_begin; *s != 0; s++)
+                if (*s == '\n')
                 {
                     line_count++;
                     if (searches_result_line_number[0] == -1 && s >= searches_input_ptr[0]) { searches_result_line_number[0] = line_count; if (--searches_remaining <= 0) break; }
@@ -3691,8 +3692,11 @@ bool ImGui::InputTextEx(const char* label, char* buf, int buf_size, const ImVec2
                     break;
                 if (rect_pos.y < clip_rect.y)
                 {
-                    p = (const ImWchar*)wmemchr((const wchar_t*)p, '\n', text_selected_end - p);
-                    p = p ? p + 1 : text_selected_end;
+                    //p = (const ImWchar*)wmemchr((const wchar_t*)p, '\n', text_selected_end - p);  // FIXME-OPT: Could use this when wchar_t are 16-bits
+                    //p = p ? p + 1 : text_selected_end;
+                    while (p < text_selected_end)
+                        if (*p++ == '\n')
+                            break;
                 }
                 else
                 {