From 02b615c8704aeda9a94cf5457c9c78de847c911a Mon Sep 17 00:00:00 2001
From: Richard Qin <richard.qin.x@gmail.com>
Date: Sun, 1 Nov 2026 02:12:34 +0800
Subject: Move support code into CoreLib

---
 libsupport/include/CoreLib/System/Errno.h | 64 +++++++++++++++++++++++++++++++
 1 file changed, 64 insertions(+)
 create mode 100644 libsupport/include/CoreLib/System/Errno.h

(limited to 'libsupport/include/CoreLib/System')

diff --git a/libsupport/include/CoreLib/System/Errno.h b/libsupport/include/CoreLib/System/Errno.h
new file mode 100644
index 0000000..2626ad9
--- /dev/null
+++ b/libsupport/include/CoreLib/System/Errno.h
@@ -0,0 +1,64 @@
+/*
+ RCC-Project
+
+ Copyright (C) 2026 Richard Qin
+
+ This file is part of RCC-Project.
+
+ RCC-Project is free software; you can redistribute it and/or modify it under
+ the terms of the GNU General Public License as published by the Free
+ Software Foundation; either version 3 of the License, or (at your option) any
+ later version.
+
+ RCC-Project is distributed in the hope that it will be useful, but WITHOUT ANY
+ WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+ A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License along with
+ RCC-Project; see the file COPYING.  If not see
+ <http://www.gnu.org/licenses/>.
+*/
+
+// This implementation is based on llvm/include/llvm/Support/Errno.h.
+
+#ifndef RCC_SUPPORT_ERRNO_H
+#define RCC_SUPPORT_ERRNO_H
+
+#include "CoreLib/Compiler/Compiler.h"
+
+#include <cerrno>
+#include <string>
+
+namespace rcc
+{
+namespace sys
+{
+
+/// Returns a string representation of the errno value, using whatever
+/// thread-safe variant of strerror() is available. Be sure to call this
+/// immediately after the function that set errno, or errno may have been
+/// overwritten by an intervening call.
+RCC_ABI std::string
+StrError ();
+
+/// Like the no-argument version above, but uses \p errnum instead of errno.
+RCC_ABI std::string
+StrError (int errnum);
+
+template <typename FailT, typename Fun, typename... Args>
+inline decltype (auto)
+RetryAfterSignal (const FailT &Fail, const Fun &F, const Args &...As)
+{
+  decltype (F (As...)) Res;
+  do
+  {
+    errno = 0;
+    Res = F (As...);
+  } while (Res == Fail && errno == EINTR);
+  return Res;
+}
+
+} // namespace sys
+} // namespace rcc
+
+#endif // RCC_SUPPORT_ERRNO_H
-- 
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