Sets the stream error state flags by assigning them the value ofstate. By default, assignsstd::ios_base::goodbit which has the effect of clearing all error state flags.

Ifrdbuf() is a null pointer (i.e. there is no associated stream buffer), thenstate|std::ios_base::badbit is assigned.

[edit]Parameters

[edit]Return value

(none)

[edit]Exceptions

If the new error state includes a bit that is also included in theexceptions() mask, throws an exception of typefailure.

[edit]Example

#include <iostream>#include <string> int main(){for(char c:{'\n','4','1','.','3','\n','Z','Y','X'})std::cin.putback(c);// emulate user's input (not portable: see ungetc Notes) double n;while(std::cout<<"Please, enter a number: "&&!(std::cin>> n)){std::cin.clear();std::string line;std::getline(std::cin, line);std::cout<< line<<"\nI am sorry, but '"<< line<<"' is not a number\n";}std::cout<< n<<"\nThank you for entering the number "<< n<<'\n';}

Please, enter a number: XYZI am sorry, but 'XYZ' is not a numberPlease, enter a number: 3.14Thank you for entering the number 3.14

[edit]Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

[edit]See also

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