LevelDB-course-Lab

Historia

costan b70493ca85 Fix fdatasync() feature detection in opensource build. The CMake feature-detection code used check_symbol_exists(), which invokes the C compiler. However, some glibc versions don't expose the fdatasync() declaration when compiled with -std=c11, but do expose it when compiled with -std=c++11. This most likely comes down to how _POSIX_SOURCE is defined -- it needs to be >= 201112L for <unistd.h> to expose fdatasync(). This CL switches to check_cxx_symbol_exists(), which uses the C++ compiler. Asides from fixing the problem above, this is the right thing to do, because we use <unistd.h> in env_posix.cc, which is compiled with the C++ compiler. This CL also fixes a previously introduced inconsistency, where the macro indicating the fdatasync() feature detection result was referred to as HAVE_FDATASYNC and HAVE_FUNC_FDATASYNC. The former appears to be used in other libraries, so this CL switches all our references to HAVE_FDATASYNC. Fixes https://github.com/google/leveldb/issues/629 ------------- Created by MOE: https://github.com/google/moe MOE_MIGRATED_REVID=228392612			5 lat temu
..
win	reverting disastrous MOE commit, returning to r21	删除	13 lat temu
README	Replace port_posix with port_stdcxx.		6 lat temu
atomic_pointer.h	Take <atomic> for granted in port/atomic_pointer.h.		6 lat temu
port.h	Replace port_posix with port_stdcxx.		6 lat temu
port_config.h.in	Fix fdatasync() feature detection in opensource build.		5 lat temu
port_example.h	Remove InitOnce from the port API.		6 lat temu
port_stdcxx.h	Remove InitOnce from the port API.		6 lat temu
thread_annotations.h	Enable thread safety annotations in open source version.		6 lat temu

README

This directory contains interfaces and implementations that isolate the
rest of the package from platform details.

Code in the rest of the package includes "port.h" from this directory.
"port.h" in turn includes a platform specific "port_<platform>.h" file
that provides the platform specific implementation.

See port_stdcxx.h for an example of what must be provided in a platform
specific header file.