Problem:
- On Apple clang version 11.0.3 (clang-1103.0.32.62) in C++17 and C++20
mode, clang 11.0.0 in C++17 and C++20 mode, and clang 9.0.1 in C++17
mode, the following error is generated:
In file included from test/compile-test.cc:16:
include/fmt/compile.h:518:25: error: implicit conversion changes signedness: 'long' to 'unsigned long' [-Werror,-Wsign-conversion]
return {f, pos + (end - str.data()) + 1, ctx.next_arg_id()};
~ ~~~~^~~~~~~~~~~~
include/fmt/compile.h:538:31: note: in instantiation of function template specialization
'fmt::v7::detail::parse_specs<int, char>' requested here
constexpr auto result = parse_specs<id_type>(str, POS + 2, ID);
^
include/fmt/compile.h:569:17: note: in instantiation of function template specialization
'fmt::v7::detail::compile_format_string<fmt::v7::detail::type_list<int>, 0, 0, FMT_COMPILE_STRING>' requested here
detail::compile_format_string<detail::type_list<Args...>, 0, 0>(
^
include/fmt/compile.h:648:37: note: in instantiation of function template specialization
'fmt::v7::detail::compile<int, FMT_COMPILE_STRING, 0>' requested here
constexpr auto compiled = detail::compile<Args...>(S());
^
test/compile-test.cc:140:24: note: in instantiation of function template specialization
'fmt::v7::format<FMT_COMPILE_STRING, int, 0>' requested here
EXPECT_EQ("42", fmt::format(FMT_COMPILE("{:x}"), 0x42));
^
In file included from test/compile-test.cc:16:
include/fmt/compile.h:518:25: error: implicit conversion changes signedness: 'long' to 'unsigned long' [-Werror,-Wsign-conversion]
return {f, pos + (end - str.data()) + 1, ctx.next_arg_id()};
~ ~~~~^~~~~~~~~~~~
include/fmt/compile.h:538:31: note: in instantiation of function template specialization
'fmt::v7::detail::parse_specs<char [4], char>' requested here
constexpr auto result = parse_specs<id_type>(str, POS + 2, ID);
^
include/fmt/compile.h:494:27: note: in instantiation of function template specialization
'fmt::v7::detail::compile_format_string<fmt::v7::detail::type_list<int, int, char const (&)[4], int>, 5, 2, FMT_COMPILE_STRING>'
requested here
constexpr auto tail = compile_format_string<Args, POS, ID>(format_str);
^
include/fmt/compile.h:539:14: note: in instantiation of function template specialization
'fmt::v7::detail::parse_tail<fmt::v7::detail::type_list<int, int, char const (&)[4], int>, 5, 2, fmt::v7::detail::spec_field<char, int, 0>, FMT_COMPILE_STRING>' requested here
return parse_tail<Args, result.end, result.next_arg_id>(
^
include/fmt/compile.h:569:17: note: in instantiation of function template specialization
'fmt::v7::detail::compile_format_string<fmt::v7::detail::type_list<int, int, char const (&)[4], int>, 0, 0, FMT_COMPILE_STRING>'
requested here
detail::compile_format_string<detail::type_list<Args...>, 0, 0>(
^
include/fmt/compile.h:648:37: note: in instantiation of function template specialization
'fmt::v7::detail::compile<int, int, char const (&)[4], int, FMT_COMPILE_STRING, 0>' requested here
constexpr auto compiled = detail::compile<Args...>(S());
^
test/compile-test.cc:145:18: note: in instantiation of function template specialization
'fmt::v7::format<FMT_COMPILE_STRING, int, int, char const (&)[4], int, 0>' requested here
fmt::format(FMT_COMPILE("{:{}}{:{}}"), 42, 4, "foo", 5));
^
2 errors generated.
Solution:
- Explicitly cast the result of the subtraction to the (unsigned) outer
type.
Co-authored-by: Jonathan Gopel <jgopel@quantlab.com>
* add forgotten template argument to make_format_args which made some uses of FMT_COMPILE not work anymore after 54daa0864a, add more elaborate test cases to compile-test as regression tests
* fix old-style cast which gcc on travis thankfully doesn't accept anymore
* hopefully last forgotten (void*)
string_view_metadata was introduced to make compiled format relocatable.
However, format string compilation is an optimization and therefore
adding overhead and extra complexity for relocation is undesirable.
In most cases the string will be either static or outlive compilation
and formatting and if it doesn't, it's possible to make compiled
representation relocatale by other means.
