diff --git a/apps/shared/storage_function.cpp b/apps/shared/storage_function.cpp
index 4af8a475f..afb572634 100644
--- a/apps/shared/storage_function.cpp
+++ b/apps/shared/storage_function.cpp
@@ -9,7 +9,7 @@ using namespace Poincare;
 
 namespace Shared {
 
-char StorageFunction::k_parenthesedArgument[]("(x)");
+constexpr char StorageFunction::k_parenthesedArgument[];
 
 bool StorageFunction::BaseNameCompliant(const char * baseName, NameNotCompliantError * error) {
   assert(baseName[0] != 0);
@@ -62,9 +62,12 @@ void StorageFunction::setActive(bool active) {
 
 int StorageFunction::nameWithArgument(char * buffer, size_t bufferSize, char arg) {
   const char * functionName = fullName();
-  k_parenthesedArgument[1] = arg;
   size_t baseNameLength = SymbolAbstract::TruncateExtension(buffer, functionName, bufferSize - k_parenthesedArgumentLength);
-  return baseNameLength + strlcpy(&buffer[baseNameLength], k_parenthesedArgument, bufferSize-baseNameLength);
+  int result = baseNameLength + strlcpy(&buffer[baseNameLength], k_parenthesedArgument, bufferSize-baseNameLength);
+  if (baseNameLength+1 < bufferSize - 1) {
+    buffer[baseNameLength+1] = arg;
+  }
+  return result;
 }
 
 template<typename T>
diff --git a/apps/shared/storage_function.h b/apps/shared/storage_function.h
index 18a3591f6..954146fdc 100644
--- a/apps/shared/storage_function.h
+++ b/apps/shared/storage_function.h
@@ -15,7 +15,7 @@ public:
     ReservedName
   };
   constexpr static int k_parenthesedArgumentLength = 3;
-  static char k_parenthesedArgument[k_parenthesedArgumentLength+1];
+  static constexpr char k_parenthesedArgument[k_parenthesedArgumentLength+1] = "(x)";
   constexpr static int k_maxNameWithArgumentSize = Poincare::SymbolAbstract::k_maxNameSize + k_parenthesedArgumentLength; /* Function name and null-terminating char + "(x)" */;
   static bool BaseNameCompliant(const char * baseName, NameNotCompliantError * error = nullptr);