[libcxx-commits] [libcxx] [libc++] Replace __resize_default_init with resize_and_overwrite (PR #157121)

[Nikolas Klauser via libcxx-commits]

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@@ -34,20 +34,19 @@ inline _LIBCPP_ATTRIBUTE_FORMAT(__printf__, 1, 0) string vformat_string(const ch
 
   va_list apcopy;
   va_copy(apcopy, ap);
-  int ret = ::vsnprintf(buf.data(), buf.size(), msg, apcopy);
+  int size = ::vsnprintf(buf.data(), buf.size(), msg, apcopy);
   va_end(apcopy);
 
   string result;
-  if (static_cast<size_t>(ret) < buf.size()) {
-    result.assign(buf.data(), static_cast<size_t>(ret));
+  if (static_cast<size_t>(size) < buf.size()) {
+    result.assign(buf.data(), static_cast<size_t>(size));
   } else {
     // we did not provide a long enough buffer on our first attempt. The
     // return value is the number of bytes (excluding the null byte) that are
     // needed for formatting.
-    size_t size_with_null = static_cast<size_t>(ret) + 1;
-    result.__resize_default_init(size_with_null - 1);
-    ret = ::vsnprintf(&result[0], size_with_null, msg, ap);
-    _LIBCPP_ASSERT_INTERNAL(static_cast<size_t>(ret) == (size_with_null - 1), "TODO");
+    result.resize_and_overwrite(size, [&](char* res, size_t n) { return ::vsnprintf(res, n, msg, ap); });
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philnik777 wrote:

You have to build the library with C++23, so yes, this is C++23 only code. I guess you aren't building with CMake? Maybe something needs to be updated?

https://github.com/llvm/llvm-project/pull/157121