Disable span_constexpr_test under GCC 4.x

.github/workflows/ci.yml

@@ -100,13 +100,13 @@ jobs:
           - toolset: gcc-9
             cxxstd: "03,11,14,17,2a"
             address-model: 32,64
-            os: ubuntu-24.04
+            os: ubuntu-20.04
             install:
               - g++-9-multilib
           - toolset: gcc-10
             cxxstd: "03,11,14,17,20"
             address-model: 32,64
-            os: ubuntu-24.04
+            os: ubuntu-20.04
             install:
               - g++-10-multilib
           - toolset: gcc-11
@@ -220,15 +220,13 @@ jobs:
           - toolset: clang
             compiler: clang++-9
             cxxstd: "03,11,14,17,2a"
-            os: ubuntu-latest
-            container: ubuntu:20.04
+            os: ubuntu-20.04
             install:
               - clang-9
           - toolset: clang
             compiler: clang++-10
             cxxstd: "03,11,14,17,20"
-            os: ubuntu-latest
-            container: ubuntu:20.04
+            os: ubuntu-20.04
             install:
               - clang-10
           - toolset: clang
@@ -637,6 +635,7 @@ jobs:
       fail-fast: false
       matrix:
         include:
+          - os: ubuntu-20.04
           - os: ubuntu-22.04
           - os: ubuntu-24.04
           - os: macos-13
@@ -704,6 +703,7 @@ jobs:
       fail-fast: false
       matrix:
         include:
+          - os: ubuntu-20.04
           - os: ubuntu-22.04
           - os: ubuntu-24.04
           - os: macos-13
@@ -781,6 +781,7 @@ jobs:
       fail-fast: false
       matrix:
         include:
+          - os: ubuntu-20.04
           - os: ubuntu-22.04
           - os: ubuntu-24.04
           - os: macos-13

doc/span.qbk

@@ -38,7 +38,7 @@ and return type use spans.
 
 ```
 auto sha1(boost::span<const unsigned char> input,
-    boost::span<unsigned char, SHA_DIGEST_LENGTH> output)
+    boost::span<unsigned char, SHA_DIGEST_LENGTH> ouput)
 {
     SHA_CTX context;
     SHA1_Init(&context);

include/boost/core/bit.hpp

@@ -28,7 +28,7 @@
 # pragma intrinsic(_BitScanForward)
 # pragma intrinsic(_BitScanReverse)
 
-# if defined(_M_X64) || defined(_M_ARM64)
+# if defined(_M_X64)
 #  pragma intrinsic(_BitScanForward64)
 #  pragma intrinsic(_BitScanReverse64)
 # endif
@@ -230,7 +230,7 @@ inline int countl_impl( boost::uint16_t x ) BOOST_NOEXCEPT
 
 #endif
 
-#if defined(_MSC_VER) && (defined(_M_X64) || defined(_M_ARM64)) && defined(BOOST_CORE_HAS_BUILTIN_ISCONSTEVAL)
+#if defined(_MSC_VER) && defined(_M_X64) && defined(BOOST_CORE_HAS_BUILTIN_ISCONSTEVAL)
 
 BOOST_CXX14_CONSTEXPR inline int countl_impl( boost::uint64_t x ) BOOST_NOEXCEPT
 {
@@ -255,7 +255,7 @@ BOOST_CXX14_CONSTEXPR inline int countl_impl( boost::uint64_t x ) BOOST_NOEXCEPT
     }
 }
 
-#elif defined(_MSC_VER) && (defined(_M_X64) || defined(_M_ARM64))
+#elif defined(_MSC_VER) && defined(_M_X64)
 
 inline int countl_impl( boost::uint64_t x ) BOOST_NOEXCEPT
 {
@@ -455,7 +455,7 @@ inline int countr_impl( boost::uint16_t x ) BOOST_NOEXCEPT
 
 #endif
 
-#if defined(_MSC_VER) && (defined(_M_X64) || defined(_M_ARM64)) && defined(BOOST_CORE_HAS_BUILTIN_ISCONSTEVAL)
+#if defined(_MSC_VER) && defined(_M_X64) && defined(BOOST_CORE_HAS_BUILTIN_ISCONSTEVAL)
 
 BOOST_CXX14_CONSTEXPR inline int countr_impl( boost::uint64_t x ) BOOST_NOEXCEPT
 {
@@ -480,7 +480,7 @@ BOOST_CXX14_CONSTEXPR inline int countr_impl( boost::uint64_t x ) BOOST_NOEXCEPT
     }
 }
 
-#elif defined(_MSC_VER) && (defined(_M_X64) || defined(_M_ARM64))
+#elif defined(_MSC_VER) && defined(_M_X64)
 
 inline int countr_impl( boost::uint64_t x ) BOOST_NOEXCEPT
 {
@@ -703,7 +703,7 @@ BOOST_CXX14_CONSTEXPR inline boost::uint32_t bit_ceil_impl( boost::uint32_t x )
 {
     if( x == 0 )
     {
-        return 1;
+        return 0;
     }
 
     --x;
@@ -723,7 +723,7 @@ BOOST_CXX14_CONSTEXPR inline boost::uint64_t bit_ceil_impl( boost::uint64_t x )
 {
     if( x == 0 )
     {
-        return 1;
+        return 0;
     }
 
     --x;

include/boost/core/demangle.hpp

@@ -30,7 +30,7 @@
 
 #if defined( BOOST_CORE_HAS_CXXABI_H )
 # include <cxxabi.h>
-// For some architectures (mips, mips64, x86, x86_64) cxxabi.h in Android NDK is implemented by gabi++ library
+// For some archtectures (mips, mips64, x86, x86_64) cxxabi.h in Android NDK is implemented by gabi++ library
 // (https://android.googlesource.com/platform/ndk/+/master/sources/cxx-stl/gabi++/), which does not implement
 // abi::__cxa_demangle(). We detect this implementation by checking the include guard here.
 # if defined( __GABIXX_CXXABI_H__ )

include/boost/core/detail/assert.hpp

@@ -1,18 +0,0 @@
-/*
-Copyright 2025 Glen Joseph Fernandes
-(glenjofe@gmail.com)
-
-Distributed under the Boost Software License, Version 1.0.
-(http://www.boost.org/LICENSE_1_0.txt)
-*/
-#undef BOOST_CORE_DETAIL_ASSERT
-
-#if !defined(__clang__) && \
-    !defined(__INTEL_COMPILER) && \
-    defined(__GNUC__) && \
-    (__GNUC__ < 5)
-#define BOOST_CORE_DETAIL_ASSERT(expr) void(0)
-#else
-#include <boost/assert.hpp>
-#define BOOST_CORE_DETAIL_ASSERT(expr) BOOST_ASSERT(expr)
-#endif

include/boost/core/scoped_enum.hpp

@@ -37,7 +37,7 @@ namespace boost
   /**
    * Casts a scoped enum to its underlying type.
    *
-   * This function is useful when working with scoped enum classes, which doesn't implicitly convert to the underlying type.
+   * This function is useful when working with scoped enum classes, which doens't implicitly convert to the underlying type.
    * @param v A scoped enum.
    * @returns The underlying type.
    * @throws No-throws.

include/boost/core/span.hpp

@@ -8,12 +8,20 @@ Distributed under the Boost Software License, Version 1.0.
 #ifndef BOOST_CORE_SPAN_HPP
 #define BOOST_CORE_SPAN_HPP
 
-#include <boost/core/detail/assert.hpp>
 #include <boost/core/data.hpp>
+#include <boost/assert.hpp>
+#include <boost/config.hpp>
+#include <boost/config/workaround.hpp>
 #include <array>
 #include <iterator>
 #include <type_traits>
 
+#if BOOST_WORKAROUND(BOOST_GCC, < 50000)
+# define BOOST_CORE_SPAN_CONSTEXPR
+#else
+# define BOOST_CORE_SPAN_CONSTEXPR constexpr
+#endif
+
 namespace boost {
 
 constexpr std::size_t dynamic_extent = static_cast<std::size_t>(-1);
@@ -274,19 +282,19 @@ public:
         return span<T, C>(s_.p + O, C);
     }
 
-    constexpr span<T, dynamic_extent> first(size_type c) const {
-        return BOOST_CORE_DETAIL_ASSERT(c <= size()),
+    BOOST_CORE_SPAN_CONSTEXPR span<T, dynamic_extent> first(size_type c) const {
+        return BOOST_ASSERT(c <= size()),
             span<T, dynamic_extent>(s_.p, c);
     }
 
-    constexpr span<T, dynamic_extent> last(size_type c) const {
-        return BOOST_CORE_DETAIL_ASSERT(c <= size()),
+    BOOST_CORE_SPAN_CONSTEXPR span<T, dynamic_extent> last(size_type c) const {
+        return BOOST_ASSERT(c <= size()),
             span<T, dynamic_extent>(s_.p + (s_.n - c), c);
     }
 
-    constexpr span<T, dynamic_extent> subspan(size_type o,
+    BOOST_CORE_SPAN_CONSTEXPR span<T, dynamic_extent> subspan(size_type o,
         size_type c = dynamic_extent) const {
-        return BOOST_CORE_DETAIL_ASSERT(o <= size() &&
+        return BOOST_ASSERT(o <= size() &&
                 (c == dynamic_extent || c + o <= size())),
             span<T, dynamic_extent>(s_.p + o,
                 c == dynamic_extent ? s_.n - o : c);
@@ -304,16 +312,16 @@ public:
         return s_.n == 0;
     }
 
-    constexpr reference operator[](size_type i) const {
-        return BOOST_CORE_DETAIL_ASSERT(i < size()), s_.p[i];
+    BOOST_CORE_SPAN_CONSTEXPR reference operator[](size_type i) const {
+        return BOOST_ASSERT(i < size()), s_.p[i];
     }
 
-    constexpr reference front() const {
-        return BOOST_CORE_DETAIL_ASSERT(!empty()), *s_.p;
+    BOOST_CORE_SPAN_CONSTEXPR reference front() const {
+        return BOOST_ASSERT(!empty()), *s_.p;
     }
 
-    constexpr reference back() const {
-        return BOOST_CORE_DETAIL_ASSERT(!empty()), s_.p[s_.n - 1];
+    BOOST_CORE_SPAN_CONSTEXPR reference back() const {
+        return BOOST_ASSERT(!empty()), s_.p[s_.n - 1];
     }
 
     constexpr pointer data() const noexcept {
@@ -403,4 +411,6 @@ as_writable_bytes(span<T, E> s) noexcept
 
 } /* boost */
 
+#undef BOOST_CORE_SPAN_CONSTEXPR
+
 #endif

test/bit_ceil_test.cpp

@@ -19,15 +19,14 @@ template<class T> void test_bit_ceil( T x )
 
     T y = boost::core::bit_ceil( x );
 
-    BOOST_TEST( boost::core::has_single_bit( y ) );
-    BOOST_TEST_GE( +y, +x );
-
     if( x == 0 )
     {
-        BOOST_TEST_EQ( y, 1 );
+        BOOST_TEST_EQ( y, 0 );
     }
     else
     {
+        BOOST_TEST( boost::core::has_single_bit( y ) );
+        BOOST_TEST_GE( +y, +x );
         BOOST_TEST_LT( y >> 1, +x );
     }
 }

test/detail_iterator_test.cpp

@@ -31,7 +31,7 @@ using std::distance;
 
 */
 
-// struct C {} doesn't work with libc++.
+// struct C {} doesn't wotk with libc++.
 typedef std::forward_iterator_tag C;
 
 struct T

test/span_constexpr_test.cpp

@@ -6,7 +6,8 @@ Distributed under the Boost Software License, Version 1.0.
 (http://www.boost.org/LICENSE_1_0.txt)
 */
 #include <boost/config.hpp>
-#if !defined(BOOST_NO_CXX11_CONSTEXPR)
+#include <boost/config/workaround.hpp>
+#if !defined(BOOST_NO_CXX11_CONSTEXPR) && !BOOST_WORKAROUND(BOOST_GCC, < 50000)
 #include <boost/core/span.hpp>
 #include <boost/core/lightweight_test.hpp>
 

test/swap/swap_no_ambiguity_in_boost.cpp

@@ -9,7 +9,7 @@
 // objects to be swapped would themselves be from the boost namespace.
 // If so, boost::core::invoke_swap itself might be found by argument dependent lookup.
 // The implementation of boost::core::invoke_swap resolves this issue by giving
-// boost::core::invoke_swap two template arguments, thereby making it less specialized
+// boost::core::invoke_swap two template argumetns, thereby making it less specialized
 // than std::swap.
 
 #include <boost/core/invoke_swap.hpp>

test/swap/swap_specialized_in_global.cpp

@@ -12,7 +12,7 @@
 //Put test class in the global namespace
 #include "./swap_test_class.hpp"
 
-//Provide swap function in global namespace
+//Provide swap function in gloabl namespace
 void swap(swap_test_class& left, swap_test_class& right)
 {
   left.swap(right);