diff --git a/include/libimp/fmt.h b/include/libimp/fmt.h
index 26f37a3..dcaa329 100644
--- a/include/libimp/fmt.h
+++ b/include/libimp/fmt.h
@@ -67,8 +67,6 @@ LIBIMP_NODISCARD std::string fmt(A1 &&a1, A &&...args) {
 
 /// @brief Return the string directly.
 inline char const *to_string(char const *a) noexcept { return (a == nullptr) ? "" : a; }
-template <std::size_t N>
-inline char const *to_string(char const (&a)[N]) noexcept { return a; }
 inline std::string to_string(std::string const &a) noexcept { return a; }
 inline std::string to_string(std::string &&a) noexcept { return std::move(a); }
 LIBIMP_EXPORT std::string to_string(char const *a, span<char const> fstr) noexcept;
diff --git a/src/libimp/fmt.cpp b/src/libimp/fmt.cpp
index 5a5a8e1..6177a6b 100644
--- a/src/libimp/fmt.cpp
+++ b/src/libimp/fmt.cpp
@@ -74,8 +74,12 @@ std::string fmt_of_float(span<char const> fstr, span<char const> l) {
 
 template <typename A /*a fundamental or pointer type*/>
 std::string sprintf(std::string const &sfmt, A a) {
-  auto sz = std::snprintf(nullptr, 0, sfmt.c_str(), a);
+  char sbuf[2048];
+  auto sz = std::snprintf(sbuf, sizeof(sbuf), sfmt.c_str(), a);
   if (sz <= 0) return {};
+  if (sz < sizeof(sbuf)) {
+    return sbuf;
+  }
   std::string des;
   des.resize(sz + 1);
   if (std::snprintf(&des[0], des.size(), sfmt.c_str(), a) < 0) {
diff --git a/test/imp/test_imp_fmt.cpp b/test/imp/test_imp_fmt.cpp
index 234dfc4..0f3ee95 100644
--- a/test/imp/test_imp_fmt.cpp
+++ b/test/imp/test_imp_fmt.cpp
@@ -14,8 +14,8 @@ TEST(fmt, operator) {
 
 TEST(fmt, to_string) {
   /// @brief string
-  EXPECT_EQ(imp::to_string(""), "");
-  EXPECT_EQ(imp::to_string("%what%"), "%what%");
+  EXPECT_STREQ(imp::to_string(""), "");
+  EXPECT_STREQ(imp::to_string("%what%"), "%what%");
   EXPECT_EQ(imp::to_string("%what%", "10") , "    %what%");
   EXPECT_EQ(imp::to_string("%what%", "-10"), "%what%    ");