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![](data:image/svg+xml, %3Csvg xmlns='http://www.w3.org/2000/svg' height='64' class='font-weight-bold' style='font: 600 30.11764705882353px "SegoeUI", Arial' width='64'%3E%3Ccircle fill='hsl(9.6, 69%, 10%)' cx='32' cy='32' r='32' /%3E%3Ctext x='50%25' y='55%25' dominant-baseline='middle' text-anchor='middle' fill='%23FFF' %3ES%3C/text%3E%3C/svg%3E)
As part of input validation, I'm using std::get_time() to validate the input date that is coming in to my application.
I'm assuming below logic should set fail bit due to incorrect format but that doesn't. So, what could be the problem?
I'm using Visual studio 2019.
This is the sample code.
int main() {
std::tm timeInfo;
std::memset(&timeInfo, 0, sizeof(timeInfo));
timeInfo.tm_isdst = -1;
std::istringstream ss("2021/12/31");
ss >> std::get_time(&timeInfo, "%m/%d/%Y");
if (ss.fail() == true)
cout << "fail bit is set"<<endl;
return 0;
}
![](data:image/svg+xml, %3Csvg xmlns='http://www.w3.org/2000/svg' height='64' class='font-weight-bold' style='font: 600 30.11764705882353px "SegoeUI", Arial' width='64'%3E%3Ccircle fill='hsl(92.8, 12%, 18%)' cx='32' cy='32' r='32' /%3E%3Ctext x='50%25' y='55%25' dominant-baseline='middle' text-anchor='middle' fill='%23FFF' %3EDL%3C/text%3E%3C/svg%3E)
Your code outputs "fail bit is set" for me.
Whereas
ss >> std::get_time( &timeInfo, "%Y/%m/%d" );
doesn't.
Thank you for the response, but I could see that issue. Here is a screen shot attached.
I don't doubt that it doesn't work for you. Presumably something's different in our environments, or version of VS. I'm using the current VS 2019 16.10 Preview 2 FWIW.
Mine is:
Microsoft Visual Studio Professional 2019
Version 16.7.7
VisualStudio.16.Release/16.7.7+30621.155
16.9.4 is the latest non-preview release, you could give that a try.
Another thought that may have some effect - what's your region/locale settings? I'm UK English.
I haven't used locale before, but, I tried to add few lines by searching and this is result.
The same works (records failure) for me.
Try updating your VS just in case there was an issue that's subsequently been fixed.
![](data:image/svg+xml, %3Csvg xmlns='http://www.w3.org/2000/svg' height='64' class='font-weight-bold' style='font: 600 30.11764705882353px "SegoeUI", Arial' width='64'%3E%3Ccircle fill='hsl(256, 32%, 34%)' cx='32' cy='32' r='32' /%3E%3Ctext x='50%25' y='55%25' dominant-baseline='middle' text-anchor='middle' fill='%23FFF' %3EMT%3C/text%3E%3C/svg%3E)
get_time is part of the localization library and is impacted by things like locale. Out of curiosity what does the runtime say the output is for the time you believe to be invalid?
What is the version of the C++ language your code is compiling for?
Thank you for the response. Here is a screenshot.
Not that it should matter but you seem to be missing a few VS updates. The C++ language standard just says Default but doesn't print out the version. I'm assuming ISO C++ 14 which is what my latest version is.
I tried changing that to C++ 14 and C++ 17, but, there is no change in result.
Out of curiosity what does the runtime say the output is for the time you believe to be invalid?
>
Sorry, If I didn't understand your question correctly. I'm assuming you were asking about the output. Isn't it?
"fail bit not set" was the output when I run that.
You are printing a message if the conversion failed or not. If the conversion didn't fail then timeInfo will contain the parsed value. What is the value of this when it says the conversion was successful?