std::string::npos

public static member constant

<string>

std::string::npos

static const size_t npos = -1;

Maximum value for size_t

npos is a static member constant value with the greatest possible value for an element of type  size_t.

This value, when used as the value for a  len (or  sublen) parameter in  string's member functions, means  "until the end of the string".

As a return value, it is usually used to indicate no matches.

This constant is defined with a value of  -1, which because  size_t is an unsigned integral type, it is the largest possible representable value for this type.