Stop overwriting errno in base::StringPrintf, StringAppendV, and StringToDouble

base/strings/string_number_conversions.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/strings/string_number_conversions.h"
 
 #include <ctype.h>
 #include <errno.h>
 #include <stdlib.h>
 #include <wctype.h>
 
 #include <limits>
 
 #include "base/logging.h"
+#include "base/scoped_clear_errno.h"
 #include "base/third_party/dmg_fp/dmg_fp.h"
 #include "base/utf_string_conversions.h"
 
 namespace base {
 
 namespace {
 
 template <typename STR, typename INT, typename UINT, bool NEG>
 struct IntToStringT {
   // This is to avoid a compiler warning about unary minus on unsigned type.
@@ skipping 418 matching lines @@
 
 bool StringToSizeT(const StringPiece& input, size_t* output) {
   return StringToIntImpl(input, output);
 }
 
 bool StringToSizeT(const StringPiece16& input, size_t* output) {
   return String16ToIntImpl(input, output);
 }
 
 bool StringToDouble(const std::string& input, double* output) {
-  errno = 0;  // Thread-safe?  It is on at least Mac, Linux, and Windows.
+  // Thread-safe?  It is on at least Mac, Linux, and Windows.
+  ScopedClearErrno clear_errno;
+
   char* endptr = NULL;
   *output = dmg_fp::strtod(input.c_str(), &endptr);
 
   // Cases to return false:
   //  - If errno is ERANGE, there was an overflow or underflow.
   //  - If the input string is empty, there was nothing to parse.
   //  - If endptr does not point to the end of the string, there are either
   //    characters remaining in the string after a parsed number, or the string
   //    does not begin with a parseable number.  endptr is compared to the
   //    expected end given the string's stated length to correctly catch cases
@@ skipping 40 matching lines @@
 bool HexStringToUInt64(const StringPiece& input, uint64* output) {
   return IteratorRangeToNumber<HexIteratorRangeToUInt64Traits>::Invoke(
       input.begin(), input.end(), output);
 }
 
 bool HexStringToBytes(const std::string& input, std::vector<uint8>* output) {
   return HexStringToBytesT(input, output);
 }
 
 }  // namespace base