Added FMT_IMPORT_STD feature macro (#3928)

include/fmt/args.h

@@ -8,9 +8,11 @@
 #ifndef FMT_ARGS_H_
 #define FMT_ARGS_H_
 
+#ifndef FMT_IMPORT_STD
 #  include <functional>  // std::reference_wrapper
 #  include <memory>      // std::unique_ptr
 #  include <vector>
+#endif
 
 #include "format.h"  // std_string_view
 

include/fmt/base.h

@@ -12,9 +12,13 @@
 #include <stdio.h>   // FILE
 #include <string.h>  // strlen
 
+#ifndef FMT_IMPORT_STD
 // <cstddef> is also included transitively from <type_traits>.
 #  include <cstddef>      // std::byte
 #  include <type_traits>  // std::enable_if
+#else
+import std;
+#endif
 
 // The fmt library version in the form major * 10000 + minor * 100 + patch.
 #define FMT_VERSION 100202

include/fmt/chrono.h

@@ -8,6 +8,7 @@
 #ifndef FMT_CHRONO_H_
 #define FMT_CHRONO_H_
 
+#ifndef FMT_IMPORT_STD
 #  include <algorithm>
 #  include <chrono>
 #  include <cmath>    // std::isfinite
@@ -17,6 +18,7 @@
 #  include <locale>
 #  include <ostream>
 #  include <type_traits>
+#endif
 
 #include "format.h"
 

include/fmt/compile.h

@@ -8,7 +8,9 @@
 #ifndef FMT_COMPILE_H_
 #define FMT_COMPILE_H_
 
+#ifndef FMT_IMPORT_STD
 #  include <iterator>  // std::back_inserter
+#endif
 
 #include "format.h"
 

include/fmt/format-inl.h

@@ -8,13 +8,15 @@
 #ifndef FMT_FORMAT_INL_H_
 #define FMT_FORMAT_INL_H_
 
+#ifndef FMT_IMPORT_STD
 #  include <algorithm>
-#include <cerrno>  // errno
-#include <climits>
 #  include <cmath>
 #  include <exception>
+#endif
+#include <cerrno>  // errno
+#include <climits>
 
-#ifndef FMT_STATIC_THOUSANDS_SEPARATOR
+#if !defined(FMT_STATIC_THOUSANDS_SEPARATOR) && !defined(FMT_IMPORT_STD)
 #  include <locale>
 #endif
 

include/fmt/format.h

@@ -38,6 +38,7 @@
 #  define FMT_REMOVE_TRANSITIVE_INCLUDES
 #endif
 
+#ifndef FMT_IMPORT_STD
 #  include <cmath>             // std::signbit
 #  include <cstdint>           // uint32_t
 #  include <cstring>           // std::memcpy
@@ -50,18 +51,22 @@
 #  include <stdexcept>     // std::runtime_error
 #  include <string>        // std::string
 #  include <system_error>  // std::system_error
+#endif
 
 #include "base.h"
 
 // Checking FMT_CPLUSPLUS for warning suppression in MSVC.
-#if FMT_HAS_INCLUDE(<bit>) && FMT_CPLUSPLUS > 201703L
+#if FMT_HAS_INCLUDE(<bit>) && FMT_CPLUSPLUS > 201703L && \
+    !defined(FMT_IMPORT_STD)
 #  include <bit>  // std::bit_cast
 #endif
 
 // libc++ supports string_view in pre-c++17.
 #if FMT_HAS_INCLUDE(<string_view>) && \
     (FMT_CPLUSPLUS >= 201703L || defined(_LIBCPP_VERSION))
+#  ifndef FMT_IMPORT_STD
 #    include <string_view>
+#  endif
 #  define FMT_USE_STRING_VIEW
 #endif
 

include/fmt/os.h

@@ -9,9 +9,11 @@
 #define FMT_OS_H_
 
 #include <cerrno>
+#ifndef FMT_IMPORT_STD
 #  include <cstddef>
 #  include <cstdio>
 #  include <system_error>  // std::system_error
+#endif
 
 #include "format.h"
 

include/fmt/ostream.h

@@ -8,7 +8,9 @@
 #ifndef FMT_OSTREAM_H_
 #define FMT_OSTREAM_H_
 
+#ifndef FMT_IMPORT_STD
 #  include <fstream>  // std::filebuf
+#endif
 
 #ifdef _WIN32
 #  ifdef __GLIBCXX__

include/fmt/printf.h

@@ -8,8 +8,10 @@
 #ifndef FMT_PRINTF_H_
 #define FMT_PRINTF_H_
 
+#ifndef FMT_IMPORT_STD
 #  include <algorithm>  // std::max
 #  include <limits>     // std::numeric_limits
+#endif
 
 #include "format.h"
 

include/fmt/ranges.h

@@ -8,10 +8,12 @@
 #ifndef FMT_RANGES_H_
 #define FMT_RANGES_H_
 
+#ifndef FMT_IMPORT_STD
 #  include <initializer_list>
 #  include <iterator>
 #  include <tuple>
 #  include <type_traits>
+#endif
 
 #include "format.h"
 

include/fmt/std.h

@@ -8,6 +8,7 @@
 #ifndef FMT_STD_H_
 #define FMT_STD_H_
 
+#ifndef FMT_IMPORT_STD
 #  include <atomic>
 #  include <bitset>
 #  include <complex>
@@ -19,6 +20,7 @@
 #  include <typeinfo>
 #  include <utility>
 #  include <vector>
+#endif
 
 #include "format.h"
 #include "ostream.h"
@@ -26,6 +28,8 @@
 #if FMT_HAS_INCLUDE(<version>)
 #  include <version>
 #endif
+
+#ifndef FMT_IMPORT_STD
 // Checking FMT_CPLUSPLUS for warning suppression in MSVC.
 #  if FMT_CPLUSPLUS >= 201703L
 #    if FMT_HAS_INCLUDE(<filesystem>)
@@ -46,6 +50,7 @@
 #  if FMT_CPLUSPLUS > 201703L && FMT_HAS_INCLUDE(<source_location>)
 #    include <source_location>
 #  endif
+#endif
 
 // GCC 4 does not support FMT_HAS_INCLUDE.
 #if FMT_HAS_INCLUDE(<cxxabi.h>) || defined(__GLIBCXX__)

include/fmt/xchar.h

@@ -8,13 +8,15 @@
 #ifndef FMT_XCHAR_H_
 #define FMT_XCHAR_H_
 
+#ifndef FMT_IMPORT_STD
 #  include <cwchar>
+#endif
 
 #include "color.h"
 #include "format.h"
 #include "ranges.h"
 
-#ifndef FMT_STATIC_THOUSANDS_SEPARATOR
+#if !defined(FMT_STATIC_THOUSANDS_SEPARATOR) && !defined(FMT_IMPORT_STD)
 #  include <locale>
 #endif
 

src/fmt.cc

@@ -2,10 +2,9 @@ module;
 
 // Put all implementation-provided headers into the global module fragment
 // to prevent attachment to this module.
+#ifndef FMT_IMPORT_STD
 #  include <algorithm>
-#include <cerrno>
 #  include <chrono>
-#include <climits>
 #  include <cmath>
 #  include <cstddef>
 #  include <cstdint>
@@ -33,6 +32,14 @@ module;
 #  include <utility>
 #  include <variant>
 #  include <vector>
+#else
+#  include <limits.h>
+#  include <stdint.h>
+#  include <stdio.h>
+#  include <time.h>
+#endif
+#include <cerrno>
+#include <climits>
 #include <version>
 
 #if __has_include(<cxxabi.h>)