C++ 对重载函数的不明确调用 - std::to_string
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Ambiguous call to overloaded function - std::to_string
提问by ShenDraeg
In attempting to insert integer values into a string, I thought that my prayers were answered when I found std::to_string, but for some reason whenever I actually try to use it, Visual Studio complains about ambiguity. Here is the current incarnation of my function:
在尝试将整数值插入字符串时，我认为当我找到 std::to_string 时我的祈祷得到了回应，但出于某种原因，每当我真正尝试使用它时，Visual Studio 都会抱怨歧义。这是我的功能的当前化身：
string get_time_remaining (int elapsed)
{
string remaining;
string temp_string;
int time_remaining = TimeLimit - elapsed;
int temp_int;
temp_int = int(time_remaining / 3600);
if(temp_int == 0)
remaining = "00 : ";
else
{
temp_string = std::to_string(temp_int); // Here!
remaining = temp_string + " : ";
}
temp_int = time_remaining % 60 + 1;
if(temp_int < 10)
remaining = remaining + "0";
temp_string = std::to_string(temp_int);
remaining = remaining + temp_string;
return remaining;
}
I have tried casting temp_int inside the call to to_string, and as you can see I even tried casting the result of what should be integer division, but no matter what I do, VS spits this out at me:
我尝试在 to_string 的调用中转换 temp_int，正如你所看到的，我什至尝试转换应该是整数除法的结果，但无论我做什么，VS 都会向我吐槽：
d:\my programs\powerplay\powerplay\powerplay.cpp(1285): error C2668: 'std::to_string' : ambiguous call to overloaded function
1> d:\microsoft visual studio 10.0\vc\include\string(688): could be 'std::string std::to_string(long double)'
1> d:\microsoft visual studio 10.0\vc\include\string(680): or 'std::string std::to_string(_ULonglong)'
1> d:\microsoft visual studio 10.0\vc\include\string(672): or 'std::string std::to_string(_Longlong)'
Any help would be appreciated.
任何帮助，将不胜感激。
回答by Rapptz
MSVC11 lacks the proper overloads for std::to_stringso you have to do a static_castto unsigned long longor long long
MSVC11缺少适当的重载std::to_string，所以你必须做static_cast对unsigned long long或long long
Note that this bug is fixed in the November CTP 2012. Which you can get here.
请注意，此错误已在 2012 年 11 月的 CTP 中修复。您可以在此处获取。
回答by Naps62
temp_intis a intvalue, and Visual Studio seems to detect only overloads which receive either double, long longor unsigned long longvalues, so it doesn't know which overload to use, thus the ambiguity (although it would seem intuitive to cast integer to long values)
temp_int是一个int值，而 Visual Studio 似乎只检测接收double,long long或unsigned long long值的重载，因此它不知道要使用哪个重载，因此存在歧义（尽管将整数转换为长值似乎很直观）
Either declare temp_intas a long long, or cast it when invoking the function
要么声明temp_int为 a long long，要么在调用函数时将其强制转换
