[flang] Fix ISO_C_BINDING type sizes for Windows (#172034)

vtjnash · claude · web-flow · commit 44f59bae39f0 · 2026-01-19T09:57:15.000-05:00
Fix several ISO_C_BINDING type parameters for Windows compatibility: - c_long/c_unsigned_long: Use 32-bit on Windows (LLP64 data model) - c_long_double: Use 64-bit (kind=8) on Windows ARM64 Windows-on-ARM-Experiments/mingw-woarm64-build#9 (comment) - c_unsigned_long_long: Explicitly use c_uint64_t instead of depending on c_unsigned_long - c_uintmax_t: Use 64-bit on Windows (consistent with MSVC/MinGW) Fixes issue reported in msys2/MINGW-packages#16579 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
diff --git a/flang/module/iso_c_binding.f90 b/flang/module/iso_c_binding.f90
@@ -43,7 +43,11 @@ module iso_c_binding
   integer, parameter, public :: &
     c_int = c_int32_t, &
     c_short = c_int16_t, &
+#if defined(_WIN32)
+    c_long = c_int32_t, &
+#else
     c_long = c_int64_t, &
+#endif
     c_long_long = c_int64_t, &
     c_signed_char = c_int8_t, &
     c_size_t = kind(c_sizeof(1)), &
@@ -74,8 +78,10 @@ module iso_c_binding
   integer, parameter, public :: &
     c_float = 4, &
     c_double = 8, &
-#if __x86_64__
+#if defined(__x86_64__)
     c_long_double = 10
+#elif defined(_WIN32) && defined(__aarch64__)
+    c_long_double = 8
 #else
     c_long_double = 16
 #endif
@@ -117,9 +123,13 @@ module iso_c_binding
     c_unsigned_char = c_uint8_t, &
     c_unsigned_short = c_uint16_t, &
     c_unsigned = c_uint32_t, &
+#if defined(_WIN32)
+    c_unsigned_long = c_uint32_t, &
+#else
     c_unsigned_long = c_uint64_t, &
-    c_unsigned_long_long = c_unsigned_long, &
-#if __powerpc__
+#endif
+    c_unsigned_long_long = c_uint64_t, &
+#if defined(__powerpc__) || defined(_WIN32)
     c_uintmax_t = c_uint64_t
 #else
     c_uintmax_t = c_uint128_t
