FreeBSD Manual Pages
std::basic_...nd_first_of(3) C++ Standard Libary std::basic_...nd_first_of(3) NAME std::basic_string::find_first_of - std::basic_string::find_first_of Synopsis size_type find_first_of( const (until basic_string& str, size_type pos = 0 C++11) ) const; size_type find_first_of( const (since basic_string& str, C++11) size_type pos = 0 ) const noexcept; (until C++20) constexpr size_type find_first_of( (since const basic_string& str, C++20) size_type pos = 0 ) const noexcept; size_type find_first_of( const (until CharT* s, size_type pos, size_type C++20) count ) const; constexpr size_type find_first_of( const CharT* s, (since size_type pos, size_type count ) C++20) const; size_type find_first_of( const (until CharT* s, size_type pos = 0 ) const; C++20) constexpr size_type find_first_of( (since const CharT* s, size_type pos = 0 ) C++20) const; size_type find_first_of( CharT ch, (until size_type pos = 0 ) const; (1) C++11) (since size_type find_first_of( CharT ch, C++11) size_type pos = 0 ) const noexcept; (until C++20) constexpr size_type find_first_of( (2) (since CharT ch, size_type pos = 0 ) const C++20) noexcept; template < class StringViewLike > (3) size_type (since find_first_of( const StringViewLike& (4) C++17) t, (until C++20) size_type pos = 0 ) const noexcept(/* see below */); (5) template < class StringViewLike > constexpr size_type find_first_of( const StringViewLike& (since t, C++20) size_type pos = 0 ) const noexcept(/* see below */); Finds the first character equal to one of the characters in the given character sequence. The search considers only the interval [pos, size()). If the character is not present in the interval, npos will be returned. 1) Finds the first character equal to one of the characters in str. 2) Finds the first character equal to one of the characters in the range [s, s+count). This range can include null characters. 3) Finds the first character equal to one of the characters in char- acter string pointed to by s. The length of the string is determined by the first null character using Traits::length(s). 4) Finds the first character equal to ch. 5) Implicitly converts t to a string view sv as if by std::ba- sic_string_view<CharT, Traits> sv = t;, then finds the first character equal to one of the characters in sv. This overload participates in overload resolution only if std::is_convertible_v<const StringViewLike&, std::ba- sic_string_view<CharT, Traits>> is true and std::is_convertible_v<const StringViewLike&, const CharT*> is false. Parameters str - string identifying characters to search for pos - position at which to begin searching count - length of character string identifying characters to search for s - pointer to a character string identifying characters to search for ch - character to search for t - object (convertible to std::basic_string_view) identifying characters to search for Return value Position of the found character or npos if no such character is found. Exceptions 5) noexcept specification: noexcept(std::is_nothrow_convertible_v<const T&, std::ba- sic_string_view<CharT, Traits>>) Notes Traits::eq() is used to perform the comparison. Example // Run this code #include <cassert> #include <iostream> #include <string> #include <string_view> int main() { using namespace std::string_literals; std::string::size_type sz; // (1) sz = "alignas"s.find_first_of("klmn"s); // assert(sz == 1); sz = "alignof"s.find_first_of("wxyz"s); // assert(sz == std::string::npos); // (2) const char* buf = "xyzabc"; sz = "consteval"s.find_first_of(buf, 0, 3); // assert(sz == std::string::npos); sz = "consteval"s.find_first_of(buf, 0, 6); // c in buf assert(sz == 0); // (3) sz = "decltype"s.find_first_of(buf); // c in buf assert(sz == 2); // (4) sz = "co_await"s.find_first_of('a'); // assert(sz == 3); // (5) std::string_view sv{"int"}; sz = "constinit"s.find_first_of(sv); // n in sv assert(sz == 2); std::cout << "All tests passed.\n"; } Possible output: All tests passed. Defect reports The following behavior-changing defect reports were applied retroac- tively to previously published C++ standards. DR Applied to Behavior as published Correct behavior LWG 2064 C++11 overload (3) and (4) were noexcept re- moved LWG 2946 C++17 string_view overload causes ambiguity in avoided by making it a some cases tem- plate P1148R0 C++11 noexcept for overload (4)/(5) was re- stored C++17 accidently dropped by LWG2064/LWG2946 See also find find characters in the string (public member function) rfind find the last occurrence of a substring (public member function) find_first_not_of find first absence of characters (public member function) find_last_of find last occurrence of characters (public member function) find_last_not_of find last absence of characters (public member function) find_first_of find first occurrence of characters (C++17) (public member function of std::ba- sic_string_view<CharT,Traits>) returns the length of the maximum initial segment that consists strspn of only the characters found in another byte string (function) http://cppreference.com 2022.07.31 std::basic_...nd_first_of(3)
NAME | Synopsis | Parameters | Return value | Exceptions | Notes | Example | Possible output: | See also
Want to link to this manual page? Use this URL:
<https://man.freebsd.org/cgi/man.cgi?query=std::u32string::find_first_of&sektion=3&manpath=FreeBSD+Ports+15.0>