diff --git a/flang/runtime/format-implementation.h b/flang/runtime/format-implementation.h
--- a/flang/runtime/format-implementation.h
+++ b/flang/runtime/format-implementation.h
@@ -353,7 +353,7 @@
       ++offset_;
     }
   } else if (edit.descriptor == 'D' && Capitalize(PeekNext()) == 'T') {
-    // DT'iotype'(v_list) user-defined derived type I/O
+    // DT['iotype'][(v_list)] user-defined derived type I/O
     edit.descriptor = DataEdit::DefinedDerivedType;
     ++offset_;
     if (auto quote{static_cast<char>(PeekNext())};
diff --git a/flang/runtime/io-api.cpp b/flang/runtime/io-api.cpp
--- a/flang/runtime/io-api.cpp
+++ b/flang/runtime/io-api.cpp
@@ -215,7 +215,7 @@
                                         : "formatted input",
                false, DIR)
         ? &child->BeginIoStatement<ChildFormattedIoStatementState<DIR>>(
-              *child, sourceFile, sourceLine)
+              *child, format, formatLength, sourceFile, sourceLine)
         : nullptr;
   } else {
     IoErrorHandler handler{terminator};
diff --git a/flang/runtime/io-error.cpp b/flang/runtime/io-error.cpp
--- a/flang/runtime/io-error.cpp
+++ b/flang/runtime/io-error.cpp
@@ -59,10 +59,14 @@
 
 void IoErrorHandler::Forward(
     int ioStatOrErrno, const char *msg, std::size_t length) {
-  SignalError(ioStatOrErrno);
-  if (ioStat_ != IostatOk && (flags_ & hasIoMsg)) {
+  if (ioStat_ != IostatOk && msg && (flags_ & hasIoMsg)) {
     ioMsg_ = SaveDefaultCharacter(msg, length, *this);
   }
+  if (ioStatOrErrno != IostatOk && msg) {
+    SignalError(ioStatOrErrno, "%.*s", static_cast<int>(length), msg);
+  } else {
+    SignalError(ioStatOrErrno);
+  }
 }
 
 void IoErrorHandler::SignalErrno() { SignalError(errno); }