README.md
1<!--
2Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
3
4SPDX-License-Identifier: curl
5-->
6
7# Building curl with Visual C++
8
9 This document describes how to compile, build and install curl and libcurl
10 from sources using the Visual C++ build tool. To build with VC++, you will of
11 course have to first install VC++. The minimum required version of VC is 6
12 (part of Visual Studio 6). However using a more recent version is strongly
13 recommended.
14
15 VC++ is also part of the Windows Platform SDK. You do not have to install the
16 full Visual Studio or Visual C++ if all you want is to build curl.
17
18 The latest Platform SDK can be downloaded freely from [Windows SDK and
19 emulator
20 archive](https://developer.microsoft.com/en-us/windows/downloads/sdk-archive)
21
22## Prerequisites
23
24 If you wish to support zlib, OpenSSL, c-ares, ssh2, you will have to download
25 them separately and copy them to the `deps` directory as shown below:
26
27 somedirectory\
28 |_curl-src
29 | |_winbuild
30 |
31 |_deps
32 |_ lib
33 |_ include
34 |_ bin
35
36 It is also possible to create the `deps` directory in some other random places
37 and tell the `Makefile` its location using the `WITH_DEVEL` option.
38
39## Building straight from git
40
41 When you check out code git and build it, as opposed from a released source
42 code archive, you need to first run the `buildconf.bat` batch file (present
43 in the source code root directory) to set things up.
44
45## Open a command prompt
46
47Open a Visual Studio Command prompt:
48
49 Using the **'Developer Command Prompt for VS [version]'** menu entry: where
50 [version} is the Visual Studio version. The developer prompt at default uses
51 the x86 mode. It is required to call `Vcvarsall.bat` to setup the prompt for
52 the machine type you want. This type of command prompt may not exist in all
53 Visual Studio versions.
54
55 See also: [Developer Command Prompt for Visual
56 Studio](https://docs.microsoft.com/en-us/dotnet/framework/tools/developer-command-prompt-for-vs)
57 and [How to: Enable a 64-Bit, x64 hosted MSVC toolset on the command
58 line](https://docs.microsoft.com/en-us/cpp/build/how-to-enable-a-64-bit-visual-cpp-toolset-on-the-command-line)
59
60 Using the **'VS [version] [platform] [type] Command Prompt'** menu entry:
61 where [version] is the Visual Studio version, [platform] is e.g. x64 and
62 [type] Native of Cross platform build. This type of command prompt may not
63 exist in all Visual Studio versions.
64
65 See also: [Set the Path and Environment Variables for Command-Line Builds](https://docs.microsoft.com/en-us/cpp/build/building-on-the-command-line)
66
67## Build in the console
68
69 Once you are in the console, go to the winbuild directory in the Curl
70 sources:
71
72 cd curl-src\winbuild
73
74 Then you can call `nmake /f Makefile.vc` with the desired options (see
75 below). The builds will be in the top src directory, `builds\` directory, in
76 a directory named using the options given to the nmake call.
77
78 nmake /f Makefile.vc mode=<static or dll> <options>
79
80where `<options>` is one or many of:
81
82 - `VC=<num>` - VC version. 6 or later.
83 - `WITH_DEVEL=<path>` - Paths for the development files (SSL, zlib, etc.)
84 Defaults to sibling directory: `../deps`
85 - `WITH_SSL=<dll/static>` - Enable OpenSSL support, DLL or static
86 - `WITH_NGHTTP2=<dll/static>` - Enable HTTP/2 support, DLL or static
87 - `WITH_MSH3=<dll/static>` - Enable (experimental) HTTP/3 support, DLL or static
88 - `WITH_MBEDTLS=<dll/static>` - Enable mbedTLS support, DLL or static
89 - `WITH_CARES=<dll/static>` - Enable c-ares support, DLL or static
90 - `WITH_ZLIB=<dll/static>` - Enable zlib support, DLL or static
91 - `WITH_SSH=<dll/static>` - Enable libSSH support, DLL or static
92 - `WITH_SSH2=<dll/static>` - Enable libSSH2 support, DLL or static
93 - `WITH_PREFIX=<dir>` - Where to install the build
94 - `ENABLE_SSPI=<yes/no>` - Enable SSPI support, defaults to yes
95 - `ENABLE_IPV6=<yes/no>` - Enable IPv6, defaults to yes
96 - `ENABLE_IDN=<yes or no>` - Enable use of Windows IDN APIs, defaults to yes
97 Requires Windows Vista or later
98 - `ENABLE_SCHANNEL=<yes/no>` - Enable native Windows SSL support, defaults
99 to yes if SSPI and no other SSL library
100 - `ENABLE_OPENSSL_AUTO_LOAD_CONFIG=<yes/no>`
101 - Enable loading OpenSSL configuration
102 automatically, defaults to yes
103 - `ENABLE_UNICODE=<yes/no>` - Enable UNICODE support, defaults to no
104 - `ENABLE_WEBSOCKETS=<yes/no>` - Enable Web Socket support, defaults to no
105 - `GEN_PDB=<yes/no>` - Generate External Program Database
106 (debug symbols for release build)
107 - `DEBUG=<yes/no>` - Debug builds
108 - `MACHINE=<x86/x64/arm64>` - Target architecture (default is x86)
109 - `CARES_PATH=<path>` - Custom path for c-ares
110 - `MBEDTLS_PATH=<path>` - Custom path for mbedTLS
111 - `NGHTTP2_PATH=<path>` - Custom path for nghttp2
112 - `MSH3_PATH=<path>` - Custom path for msh3
113 - `SSH2_PATH=<path>` - Custom path for libSSH2
114 - `SSL_PATH=<path>` - Custom path for OpenSSL
115 - `ZLIB_PATH=<path>` - Custom path for zlib
116
117## Static linking of Microsoft's C runtime (CRT):
118
119 If you are using mode=static nmake will create and link to the static build
120 of libcurl but *not* the static CRT. If you must you can force nmake to link
121 in the static CRT by passing `RTLIBCFG=static`. Typically you shouldn't use
122 that option, and nmake will default to the DLL CRT. `RTLIBCFG` is rarely used
123 and therefore rarely tested. When passing `RTLIBCFG` for a configuration that
124 was already built but not with that option, or if the option was specified
125 differently, you must destroy the build directory containing the
126 configuration so that nmake can build it from scratch.
127
128 This option is not recommended unless you have enough development experience
129 to know how to match the runtime library for linking (that is, the CRT). If
130 `RTLIBCFG=static` then release builds use `/MT` and debug builds use `/MTd`.
131
132## Building your own application with libcurl (Visual Studio example)
133
134 When you build curl and libcurl, nmake will show the relative path where the
135 output directory is. The output directory is named from the options nmake used
136 when building. You may also see temp directories of the same name but with
137 suffixes -obj-curl and -obj-lib.
138
139 For example let's say you've built curl.exe and libcurl.dll from the Visual
140 Studio 2010 x64 Win64 Command Prompt:
141
142 nmake /f Makefile.vc mode=dll VC=10
143
144 The output directory will have a name similar to
145 `..\builds\libcurl-vc10-x64-release-dll-ipv6-sspi-schannel`.
146
147 The output directory contains subdirectories bin, lib and include. Those are
148 the directories to set in your Visual Studio project. You can either copy the
149 output directory to your project or leave it in place. Following the example,
150 let's assume you leave it in place and your curl top source directory is
151 `C:\curl-7.82.0`. You would set these options for configurations using the
152 x64 platform:
153
154~~~
155 - Configuration Properties > Debugging > Environment
156 PATH=C:\curl-7.82.0\builds\libcurl-vc10-x64-release-dll-ipv6-sspi-schannel\bin;%PATH%
157
158 - C/C++ > General > Additional Include Directories
159 C:\curl-7.82.0\builds\libcurl-vc10-x64-release-dll-ipv6-sspi-schannel\include;
160
161 - Linker > General > Additional Library Directories
162 C:\curl-7.82.0\builds\libcurl-vc10-x64-release-dll-ipv6-sspi-schannel\lib;
163
164 - Linker > Input > Additional Dependencies
165 libcurl.lib;
166~~~
167
168 For configurations using the x86 platform (aka Win32 platform) you would
169 need to make a separate x86 build of libcurl.
170
171 If you build libcurl static (`mode=static`) or debug (`DEBUG=yes`) then the
172 library name will vary and separate builds may be necessary for separate
173 configurations of your project within the same platform. This is discussed in
174 the next section.
175
176## Building your own application with a static libcurl
177
178 When building an application that uses the static libcurl library on Windows,
179 you must define `CURL_STATICLIB`. Otherwise the linker will look for dynamic
180 import symbols.
181
182 The static library name has an `_a` suffix in the basename and the debug
183 library name has a `_debug` suffix in the basename. For example,
184 `libcurl_a_debug.lib` is a static debug build of libcurl.
185
186 You may need a separate build of libcurl for each VC configuration combination
187 (for example: Debug|Win32, Debug|x64, Release|Win32, Release|x64).
188
189 You must specify any additional dependencies needed by your build of static
190 libcurl (for example:
191 `advapi32.lib;crypt32.lib;normaliz.lib;ws2_32.lib;wldap32.lib`).
192
193## Legacy Windows and SSL
194
195 When you build curl using the build files in this directory the default SSL
196 backend will be Schannel (Windows SSPI), the native SSL library that comes
197 with the Windows OS. Schannel in Windows <= XP is not able to connect to
198 servers that no longer support the legacy handshakes and algorithms used by
199 those versions. If you will be using curl in one of those earlier versions of
200 Windows you should choose another SSL backend like OpenSSL.
201
