Google 的开元技术 protobuf

This directory contains project files for compiling Protocol Buffers using MSVC. This is not the recommended way to do Protocol Buffer development -- we prefer to develop under a Unix-like environment -- but it may be more accessible to those who primarily work with MSVC. Compiling and Installing ======================== 1) Open protobuf.sln in Microsoft Visual Studio. 2) Choose "Debug" or "Release" configuration as desired.* 3) From the Build menu, choose "Build Solution". Wait for compiling to finish. 4) From a command shell, run tests.exe and lite-test.exe and check that all tests pass. 5) Run extract_includes.bat to copy all the public headers into a separate "include" directory (under the top-level package directory). 6) Copy the contents of the include directory to wherever you want to put headers. 7) Copy protoc.exe wherever you put build tools (probably somewhere in your PATH). 8) Copy libprotobuf.lib, libprotobuf-lite.lib, and libprotoc.lib wherever you put libraries. * To avoid conflicts between the MSVC debug and release runtime libraries, when compiling a debug build of your application, you may need to link against a debug build of libprotobuf.lib. Similarly, release builds should link against release libs. DLLs vs. static linking ======================= Static linking is now the default for the Protocol Buffer libraries. Due to issues with Win32's use of a separate heap for each DLL, as well as binary compatibility issues between different versions of MSVC's STL library, it is recommended that you use static linkage only. However, it is possible to build libprotobuf and libprotoc as DLLs if you really want. To do this, do the following: 1) Open protobuf.sln in MSVC. 2) For each of the projects libprotobuf, libprotobuf-lite, and libprotoc, do the following: 2a) Right-click the project and choose "properties". 2b) From the side bar, choose "General", under "Configuration Properties". 2c) Change the "Configuration Type" to "Dynamic Library (.dll)". 2d) From the side bar, choose "Preprocessor", under "C/C++". 2e) Add PROTOBUF_USE_DLLS to the list of preprocessor defines. 3) When compiling your project, make sure to #define PROTOBUF_USE_DLLS. When distributing your software to end users, we strongly recommend that you do NOT install libprotobuf.dll or libprotoc.dll to any shared location. Instead, keep these libraries next to your binaries, in your application's own install directory. C++ makes it very difficult to maintain binary compatibility between releases, so it is likely that future versions of these libraries will *not* be usable as drop-in replacements. If your project is itself a DLL intended for use by third-party software, we recommend that you do NOT expose protocol buffer objects in your library's public interface, and that you statically link protocol buffers into your library. ZLib support ============ If you want to include GzipInputStream and GzipOutputStream (google/protobuf/io/gzip_stream.h) in libprotoc, you will need to do a few additional steps: 1) Obtain a copy of the zlib library. The pre-compiled DLL at zlib.net works. 2) Make sure zlib's two headers are in your include path and that the .lib file is in your library path. You could place all three files directly into the vsproject directory to compile libprotobuf, but they need to be visible to your own project as well, so you should probably just put them into the VC shared icnlude and library directories. 3) Right-click on the "tests" project and choose "properties". Navigate the sidebar to "Configuration Properties" -> "Linker" -> "Input". 4) Under "Additional Dependencies", add the name of the zlib .lib file (e.g. zdll.lib). Make sure to update both the Debug and Release configurations. 5) If you are compiling libprotobuf and libprotoc as DLLs (see previous section), repeat steps 2 and 3 for the libprotobuf and libprotoc projects. If you are compiling them as static libraries, then you will need to link against the zlib library directly from your own app. 6) Edit config.h (in the vsprojects directory) and un-comment the line that #defines HAVE_ZLIB. (Or, alternatively, define this macro via the project settings.) Notes on Compiler Warnings ========================== The following warnings have been disabled while building the protobuf libraries and compiler. You may have to disable some of them in your own project as well, or live with them. C4018 - 'expression' : signed/unsigned mismatch C4146 - unary minus operator applied to unsigned type, result still unsigned C4244 - Conversion from 'type1' to 'type2', possible loss of data. C4251 - 'identifier' : class 'type' needs to have dll-interface to be used by clients of class 'type2' C4267 - Conversion from 'size_t' to 'type', possible loss of data. C4305 - 'identifier' : truncation from 'type1' to 'type2' C4355 - 'this' : used in base member initializer list C4800 - 'type' : forcing value to bool 'true' or 'false' (performance warning) C4996 - 'function': was declared deprecated C4251 is of particular note, if you are compiling the Protocol Buffer library as a DLL (see previous section). The protocol buffer library uses templates in its public interfaces. MSVC does not provide any reasonable way to export template classes from a DLL. However, in practice, it appears that exporting templates is not necessary anyway. Since the complete definition of any template is available in the header files, anyone importing the DLL will just end up compiling instances of the templates into their own binary. The Protocol Buffer implementation does not rely on static template members being unique, so there should be no problem with this, but MSVC prints warning nevertheless. So, we disable it. Unfortunately, this warning will also be produced when compiling code which merely uses protocol buffers, meaning you may have to disable it in your code too.