Add a portable strerror*() wrapper, llvm::sys::StrError(). This includes the

Windows variant, strerror_s, but I couldn't test that.

I'll update configure and config.h.in in a subsequent patch.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@74621 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/System/Errno.h

@@ -0,0 +1,34 @@
+//===- llvm/System/Errno.h - Portable+convenient errno handling -*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file declares some portable and convenient functions to deal with errno.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_SYSTEM_ERRNO_H
+#define LLVM_SYSTEM_ERRNO_H
+
+#include <string>
+
+namespace llvm {
+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.
+std::string StrError();
+
+/// Like the no-argument version above, but uses \p errnum instead of errno.
+std::string StrError(int errnum);
+
+}  // namespace sys
+}  // namespace llvm
+
+#endif  // LLVM_SYSTEM_ERRNO_H