RFR: 8336966: Alpine Linux x86_64 compilation error: sendfile64

[Brian Burkhalter]

On Tue, 23 Jul 2024 09:22:05 GMT, Jan Kratochvil <jkratochvil at openjdk.org> wrote:

> Alpine Linux 3.20 x86_64 compilation error:
> 
> 
> .../src/java.base/linux/native/libnio/ch/FileDispatcherImpl.c: In function 'Java_sun_nio_ch_FileDispatcherImpl_transferTo0':
> .../src/java.base/linux/native/libnio/ch/FileDispatcherImpl.c:117:9: error: implicit declaration of function 'sendfile64'; did you mean 'sendfile'? [-Werror=implicit-function-declaration]
>   117 | n = sendfile64(dstFD, srcFD, &offset, (size_t)count);
>       | ^~~~~~~~~~
>       | sendfile
> cc1: all warnings being treated as errors
> * For target support_native_java.base_libnio_LinuxNativeDispatcher.o:
> In file included from .../src/java.base/share/native/libjava/jni_util.h:30,
>                  from .../src/java.base/linux/native/libnio/fs/LinuxNativeDispatcher.c:27:
> .../src/java.base/linux/native/libnio/fs/LinuxNativeDispatcher.c: In function 'Java_sun_nio_fs_LinuxNativeDispatcher_directCopy0':
> .../src/java.base/linux/native/libnio/fs/LinuxNativeDispatcher.c:214:21: error: implicit declaration of function 'sendfile64'; did you mean 'sendfile'? [-Werror=implicit-function-declaration]
>   214 | RESTARTABLE(sendfile64(dst, src, NULL, count), bytes_sent);
>       | ^~~~~~~~~~
> .../src/java.base/unix/native/libjava/jni_util_md.h:31:15: note: in definition of macro 'RESTARTABLE'
>    31 | _result = _cmd; \
>       | ^~~~
> cc1: all warnings being treated as errors
> 
> `make/autoconf/flags-cflags.m4`
> 
>   if test "x$OPENJDK_TARGET_OS" = xlinux; then
>     CFLAGS_OS_DEF_JVM="-DLINUX -D_FILE_OFFSET_BITS=64"
>     CFLAGS_OS_DEF_JDK="-D_GNU_SOURCE -D_REENTRANT -D_FILE_OFFSET_BITS=64"
> 
> `sendfile64` were introduced by: #10154 and inherited from https://github.com/openjdk/jdk/commit/a449cd08d7475215fe50218312a5d858068c694c

The change looks okay and does not break our 64-bit Linux implementations.
Has it been tested on 32-bit Linux?

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PR Review: https://git.openjdk.org/jdk/pull/20295#pullrequestreview-2198011881