[libcxx-commits] [libcxx] [libc++] Support file offsets larger than 2GB in basic_filebuf on 32-bit AIX and 32-bit glibc Linux (PR #215892)

[Nikolas Klauser via libcxx-commits]

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@@ -217,6 +217,20 @@ typedef basic_fstream<wchar_t> wfstream;
 #      pragma GCC system_header
 #    endif
 
+#    if defined(_AIX) || (defined(__linux__) && defined(__GLIBC__))
+#      define _LIBCPP_HAS_LARGEFILE_API 1
+#    else
+#      define _LIBCPP_HAS_LARGEFILE_API 0
+#    endif
+
+#    if _LIBCPP_HAS_LARGEFILE_API
+// On AIX and glibc on Linux, fopen64/fseeko64/ftello64 are not guaranteed to always be declared, so we declare them
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philnik777 wrote:

The glibc claim seems wrong. At least `fseeko64` is defined if `__USE_LARGEFILE64` is defined, which in turn is defined if `_LARGEGILE64_SOURCE` is defined. That in turn is defined if `_GNU_SOURCE` is defined, which is always defined by the compiler in the cases we care about AFAICT.

https://github.com/llvm/llvm-project/pull/215892