diff --git a/src/fontdetection.cpp b/src/fontdetection.cpp
--- a/src/fontdetection.cpp
+++ b/src/fontdetection.cpp
@@ -347,7 +347,7 @@ static int CALLBACK EnumFontCallback(con
 	PLOGFONT os_data = MallocT<LOGFONT>(1);
 	*os_data = logfont->elfLogFont;
 	info->callback->SetFontNames(info->settings, font_name, os_data);
-	if (info->callback->FindMissingGlyphs(nullptr)) return 1;
+	if (info->callback->FindMissingGlyphs()) return 1;
 	DEBUG(freetype, 1, "Fallback font: %s (%s)", font_name, english_name);
 	return 0; // stop enumerating
 }
@@ -477,7 +477,7 @@ bool SetFallbackFont(FreeTypeSettings *s
 
 		/* Save result. */
 		callback->SetFontNames(settings, name);
-		if (!callback->FindMissingGlyphs(nullptr)) {
+		if (!callback->FindMissingGlyphs()) {
 			DEBUG(freetype, 2, "CT-Font for %s: %s", language_isocode, name);
 			result = true;
 			break;
@@ -488,10 +488,10 @@ bool SetFallbackFont(FreeTypeSettings *s
 		/* For some OS versions, the font 'Arial Unicode MS' does not report all languages it
 		 * supports. If we didn't find any other font, just try it, maybe we get lucky. */
 		callback->SetFontNames(settings, "Arial Unicode MS");
-		result = !callback->FindMissingGlyphs(nullptr);
+		result = !callback->FindMissingGlyphs();
 	}
 
-	callback->FindMissingGlyphs(nullptr);
+	callback->FindMissingGlyphs();
 	return result;
 }
 
@@ -623,7 +623,7 @@ bool SetFallbackFont(FreeTypeSettings *s
 
 			callback->SetFontNames(settings, (const char*)file);
 
-			bool missing = callback->FindMissingGlyphs(nullptr);
+			bool missing = callback->FindMissingGlyphs();
 			DEBUG(freetype, 1, "Font \"%s\" misses%s glyphs", file, missing ? "" : " no");
 
 			if (!missing) {
diff --git a/src/strings.cpp b/src/strings.cpp
--- a/src/strings.cpp
+++ b/src/strings.cpp
@@ -1998,11 +1998,9 @@ const char *GetCurrentLanguageIsoCode()
 
 /**
  * Check whether there are glyphs missing in the current language.
- * @param[out] str Pointer to an address for storing the text pointer.
  * @return If glyphs are missing, return \c true, else return \c false.
- * @post If \c true is returned and str is not nullptr, *str points to a string that is found to contain at least one missing glyph.
  */
-bool MissingGlyphSearcher::FindMissingGlyphs(const char **str)
+bool MissingGlyphSearcher::FindMissingGlyphs()
 {
 	InitFreeType(this->Monospace());
 	const Sprite *question_mark[FS_END];
@@ -2014,7 +2012,6 @@ bool MissingGlyphSearcher::FindMissingGl
 	this->Reset();
 	for (const char *text = this->NextString(); text != nullptr; text = this->NextString()) {
 		FontSize size = this->DefaultSize();
-		if (str != nullptr) *str = text;
 		for (WChar c = Utf8Consume(&text); c != '\0'; c = Utf8Consume(&text)) {
 			if (c >= SCC_FIRST_FONT && c <= SCC_LAST_FONT) {
 				size = (FontSize)(c - SCC_FIRST_FONT);
@@ -2095,7 +2092,7 @@ void CheckForMissingGlyphs(bool base_fon
 {
 	static LanguagePackGlyphSearcher pack_searcher;
 	if (searcher == nullptr) searcher = &pack_searcher;
-	bool bad_font = !base_font || searcher->FindMissingGlyphs(nullptr);
+	bool bad_font = !base_font || searcher->FindMissingGlyphs();
 #if defined(WITH_FREETYPE) || defined(_WIN32)
 	if (bad_font) {
 		/* We found an unprintable character... lets try whether we can find
diff --git a/src/strings_func.h b/src/strings_func.h
--- a/src/strings_func.h
+++ b/src/strings_func.h
@@ -277,7 +277,7 @@ public:
 	 */
 	virtual void SetFontNames(struct FreeTypeSettings *settings, const char *font_name, const void *os_data = nullptr) = 0;
 
-	bool FindMissingGlyphs(const char **str);
+	bool FindMissingGlyphs();
 };
 
 void CheckForMissingGlyphs(bool base_font = true, MissingGlyphSearcher *search = nullptr);