1This directory contains project files for compiling Protocol Buffers using
2MSVC. This is not the recommended way to do Protocol Buffer development --
3we prefer to develop under a Unix-like environment -- but it may be more
4accessible to those who primarily work with MSVC.
5
6Compiling and Installing
7========================
8
91) Open protobuf.sln in Microsoft Visual Studio.
102) Choose "Debug" or "Release" configuration as desired.*
113) From the Build menu, choose "Build Solution". Wait for compiling to finish.
124) From a command shell, run tests.exe and lite-test.exe and check that all
13 tests pass.
145) Run extract_includes.bat to copy all the public headers into a separate
15 "include" directory (under the top-level package directory).
166) Copy the contents of the include directory to wherever you want to put
17 headers.
187) Copy protoc.exe wherever you put build tools (probably somewhere in your
19 PATH).
208) Copy libprotobuf.lib, libprotobuf-lite.lib, and libprotoc.lib wherever you
21 put libraries.
22
23* To avoid conflicts between the MSVC debug and release runtime libraries, when
24 compiling a debug build of your application, you may need to link against a
25 debug build of libprotobuf.lib. Similarly, release builds should link against
26 release libs.
27
28DLLs vs. static linking
29=======================
30
31Static linking is now the default for the Protocol Buffer libraries. Due to
32issues with Win32's use of a separate heap for each DLL, as well as binary
33compatibility issues between different versions of MSVC's STL library, it is
34recommended that you use static linkage only. However, it is possible to
35build libprotobuf and libprotoc as DLLs if you really want. To do this,
36do the following:
37
38 1) Open protobuf.sln in MSVC.
39 2) For each of the projects libprotobuf, libprotobuf-lite, and libprotoc, do
40 the following:
41 2a) Right-click the project and choose "properties".
42 2b) From the side bar, choose "General", under "Configuration Properties".
43 2c) Change the "Configuration Type" to "Dynamic Library (.dll)".
44 2d) From the side bar, choose "Preprocessor", under "C/C++".
45 2e) Add PROTOBUF_USE_DLLS to the list of preprocessor defines.
46 3) When compiling your project, make sure to #define PROTOBUF_USE_DLLS.
47
48When distributing your software to end users, we strongly recommend that you
49do NOT install libprotobuf.dll or libprotoc.dll to any shared location.
50Instead, keep these libraries next to your binaries, in your application's
51own install directory. C++ makes it very difficult to maintain binary
52compatibility between releases, so it is likely that future versions of these
53libraries will *not* be usable as drop-in replacements.
54
55If your project is itself a DLL intended for use by third-party software, we
56recommend that you do NOT expose protocol buffer objects in your library's
57public interface, and that you statically link protocol buffers into your
58library.
59
60ZLib support
61============
62
63If you want to include GzipInputStream and GzipOutputStream
64(google/protobuf/io/gzip_stream.h) in libprotoc, you will need to do a few
65additional steps:
66
671) Obtain a copy of the zlib library. The pre-compiled DLL at zlib.net works.
682) Make sure zlib's two headers are in your include path and that the .lib file
69 is in your library path. You could place all three files directly into the
70 vsproject directory to compile libprotobuf, but they need to be visible to
71 your own project as well, so you should probably just put them into the
72 VC shared icnlude and library directories.
733) Right-click on the "tests" project and choose "properties". Navigate the
74 sidebar to "Configuration Properties" -> "Linker" -> "Input".
754) Under "Additional Dependencies", add the name of the zlib .lib file (e.g.
76 zdll.lib). Make sure to update both the Debug and Release configurations.
775) If you are compiling libprotobuf and libprotoc as DLLs (see previous
78 section), repeat steps 2 and 3 for the libprotobuf and libprotoc projects.
79 If you are compiling them as static libraries, then you will need to link
80 against the zlib library directly from your own app.
816) Edit config.h (in the vsprojects directory) and un-comment the line that
82 #defines HAVE_ZLIB. (Or, alternatively, define this macro via the project
83 settings.)
84
85Notes on Compiler Warnings
86==========================
87
88The following warnings have been disabled while building the protobuf libraries
89and compiler. You may have to disable some of them in your own project as
90well, or live with them.
91
92C4018 - 'expression' : signed/unsigned mismatch
93C4146 - unary minus operator applied to unsigned type, result still unsigned
94C4244 - Conversion from 'type1' to 'type2', possible loss of data.
95C4251 - 'identifier' : class 'type' needs to have dll-interface to be used by
96 clients of class 'type2'
97C4267 - Conversion from 'size_t' to 'type', possible loss of data.
98C4305 - 'identifier' : truncation from 'type1' to 'type2'
99C4355 - 'this' : used in base member initializer list
100C4800 - 'type' : forcing value to bool 'true' or 'false' (performance warning)
101C4996 - 'function': was declared deprecated
102
103C4251 is of particular note, if you are compiling the Protocol Buffer library
104as a DLL (see previous section). The protocol buffer library uses templates in
105its public interfaces. MSVC does not provide any reasonable way to export
106template classes from a DLL. However, in practice, it appears that exporting
107templates is not necessary anyway. Since the complete definition of any
108template is available in the header files, anyone importing the DLL will just
109end up compiling instances of the templates into their own binary. The
110Protocol Buffer implementation does not rely on static template members being
111unique, so there should be no problem with this, but MSVC prints warning
112nevertheless. So, we disable it. Unfortunately, this warning will also be
113produced when compiling code which merely uses protocol buffers, meaning you
114may have to disable it in your code too.
115