Checks if the given character is a blank character as classified by the currently installed C locale. Blank characters are whitespace characters used to separate words within a sentence. In the default C locale, only space (0x20) and horizontal tab (0x09) are classified as blank characters.

The behavior is undefined if the value ofch is not representable asunsignedchar and is not equal toEOF.

[edit]Parameters

[edit]Return value

Non-zero value if the character is a blank character, zero otherwise.

[edit]Notes

Like all other functions from<cctype>, the behavior ofstd::isblank is undefined if the argument's value is neither representable asunsignedchar nor equal toEOF. To use these functions safely with plainchars (orsignedchars), the argument should first be converted tounsignedchar:

bool my_isblank(char ch){return std::isblank(static_cast<unsignedchar>(ch));}

Similarly, they should not be directly used with standard algorithms when the iterator's value type ischar orsignedchar. Instead, convert the value tounsignedchar first:

int count_blanks(conststd::string& s){returnstd::count_if(s.begin(), s.end(),// static_cast<int(*)(int)>(std::isblank)         // wrong// [](int c){ return std::isblank(c); }           // wrong// [](char c){ return std::isblank(c); }          // wrong[](unsignedchar c){return std::isblank(c);}// correct);}

[edit]See also

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