[libcxx-commits] [libcxx] [libcxx] Fix build for glibc < 2.27 (PR #121893)

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llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-libcxx

Author: Yi Kong (kongy)

<details>
<summary>Changes</summary>

PR #<!-- -->109211 introduced a build break on systems with glibc < 2.27, since copy_file_range was only introduced after that version. A version check is added to prevent this breakage.

---
Full diff: https://github.com/llvm/llvm-project/pull/121893.diff


1 Files Affected:

- (modified) libcxx/src/filesystem/operations.cpp (+2-2) 


``````````diff
diff --git a/libcxx/src/filesystem/operations.cpp b/libcxx/src/filesystem/operations.cpp
index bd37c5af86f6c3..e68f89ab1e6114 100644
--- a/libcxx/src/filesystem/operations.cpp
+++ b/libcxx/src/filesystem/operations.cpp
@@ -39,8 +39,8 @@
 #include <fcntl.h> /* values for fchmodat */
 #include <time.h>
 
-// since Linux 4.5 and FreeBSD 13, but the Linux libc wrapper is only provided by glibc and musl
-#if (defined(__linux__) && (defined(__GLIBC__) || _LIBCPP_HAS_MUSL_LIBC)) || defined(__FreeBSD__)
+// since Linux 4.5 and FreeBSD 13, but the Linux libc wrapper is only provided by glibc >= 2.27 and musl
+#if (defined(__linux__) && (_LIBCPP_GLIBC_PREREQ(2, 27) || _LIBCPP_HAS_MUSL_LIBC)) || defined(__FreeBSD__)
 #  define _LIBCPP_FILESYSTEM_USE_COPY_FILE_RANGE
 #endif
 #if __has_include(<sys/sendfile.h>)

``````````

</details>


https://github.com/llvm/llvm-project/pull/121893