std::source_location::source_location

 

C++

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Utilities library

Language support Type support (basic types, RTTI) Library feature-test macros (C++20) Dynamic memory management Program utilities Coroutine support (C++20) Variadic functions is_constant_evaluated (C++20) is_within_lifetime (C++26) initializer_list (C++11) source_location (C++20) Three-way comparison three_way_comparablethree_way_comparable_with (C++20)(C++20) strong_ordering (C++20) weak_ordering (C++20) partial_ordering (C++20) common_comparison_category (C++20) compare_three_way_result (C++20) compare_three_way (C++20) strong_order (C++20) weak_order (C++20) partial_order (C++20) compare_strong_order_fallback (C++20) compare_weak_order_fallback (C++20) compare_partial_order_fallback (C++20)   is_eqis_ltis_lteq (C++20)(C++20)(C++20)   is_neqis_gtis_gteq (C++20)(C++20)(C++20)

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std::source_location

Member functions

Creation

source_location::source_location

source_location::current

Field access

source_location::line

source_location::column

source_location::file_name

source_location::function_name

 

constexpr source_location() noexcept;	(1)	(since C++20)
source_location( const source_location& other );	(2)	(since C++20)
source_location( source_location&& other ) noexcept;	(3)	(since C++20)

1) Constructs a source_location object of unspecified value.

2,3) Copy and move constructors. It is unspecified whether they are trivial and/or constexpr.

Parameters

other

-

another source_location to copy or move from

Example

Run this code

#include <iomanip>
#include <iostream>
#include <ranges>
#include <source_location>
#include <string_view>
#include <vector>
 
// GCC specific type name printer
#if (__GNUG__ >= 11)
template<typename T>
auto type_name_helper(const std::source_location s = std::source_location::current())
{
    using std::operator""sv;
    const std::string_view fun_name{s.function_name()};
    constexpr auto prefix{"[with T = "sv};
    const auto type_name_begin{fun_name.find(prefix)};
    if (""sv.npos == type_name_begin)
        return ""sv;
    const std::size_t first{type_name_begin + prefix.length()};
    return std::string_view{fun_name.cbegin() + first, fun_name.cend() - 1};
}
 
template<typename T>
auto type_name() { return type_name_helper<T>(); }
#endif
 
void print(std::string_view const comment, std::source_location const l)
{
    std::cout << comment << ":\n"
              << "  file_name     : " << std::quoted(l.file_name()) << '\n'
              << "  function_name : " << std::quoted(l.function_name()) << '\n'
              << "  line          : " << l.line() << '\n'
              << "  column        : " << l.column() << '\n';
}
 
int main()
{
    constexpr std::source_location default_constructed;
    print("default constructed", default_constructed);
 
    constexpr std::source_location current = std::source_location::current();
    print("current", current);
 
#if (__GNUG__ >= 11)
    const std::vector<std::vector<int>> v{{1,2}, {3,4,5}, {6}};
    auto jv = std::ranges::join_view(v);
    std::cout << '\n'
              << '[' << type_name<int>() << "]\n"
              << '[' << type_name<double*>() << "]\n"
              << '[' << type_name<decltype([](){})>() << "]\n"
              << '[' << type_name<decltype(type_name<int>())>() << "]\n"
              << '[' << type_name<decltype(jv)>() << "]\n";
#endif
}

Possible output:

default constructed:
  file_name     : ""
  function_name : ""
  line          : 0
  column        : 0
current:
  file_name     : "main.cpp"
  function_name : "int main()"
  line          : 39
  column        : 75
 
[int]
[double*]
[main()::<lambda()>]
[std::basic_string_view<char>]
[std::ranges::join_view<std::ranges::ref_view<const std::vector<std::vector<int> > > >]

See also

current [static]	constructs a new source_location corresponding to the location of the call site (public static member function)
(constructor)	constructs a new stacktrace_entry (public member function of std::stacktrace_entry)