README.md
1# Building curl with Visual C++
2
3 This document describes how to compile, build and install curl and libcurl
4 from sources using the Visual C++ build tool. To build with VC++, you will of
5 course have to first install VC++. The minimum required version of VC is 6
6 (part of Visual Studio 6). However using a more recent version is strongly
7 recommended.
8
9 VC++ is also part of the Windows Platform SDK. You do not have to install the
10 full Visual Studio or Visual C++ if all you want is to build curl.
11
12 The latest Platform SDK can be downloaded freely from [Windows SDK and
13 emulator
14 archive](https://developer.microsoft.com/en-us/windows/downloads/sdk-archive)
15
16## Prerequisites
17
18 If you wish to support zlib, openssl, c-ares, ssh2, you will have to download
19 them separately and copy them to the deps directory as shown below:
20
21 somedirectory\
22 |_curl-src
23 | |_winbuild
24 |
25 |_deps
26 |_ lib
27 |_ include
28 |_ bin
29
30 It is also possible to create the deps directory in some other random places
31 and tell the Makefile its location using the WITH_DEVEL option.
32
33## Building straight from git
34
35 When you check out code git and build it, as opposed from a released source
36 code archive, you need to first run the `buildconf.bat` batch file (present
37 in the source code root directory) to set things up.
38
39## Open a command prompt
40
41Open a Visual Studio Command prompt:
42
43 Using the **'Developer Command Prompt for VS [version]'** menu entry: where
44 [version} is the Visual Studio version. The developer prompt at default uses
45 the x86 mode. It is required to call `Vcvarsall.bat` to setup the prompt for
46 the machine type you want. This type of command prompt may not exist in all
47 Visual Studio versions.
48
49 See also: [Developer Command Prompt for Visual
50 Studio](https://docs.microsoft.com/en-us/dotnet/framework/tools/developer-command-prompt-for-vs)
51 and [How to: Enable a 64-Bit, x64 hosted MSVC toolset on the command
52 line](https://docs.microsoft.com/en-us/cpp/build/how-to-enable-a-64-bit-visual-cpp-toolset-on-the-command-line)
53
54 Using the **'VS [version] [platform] [type] Command Prompt'** menu entry:
55 where [version] is the Visual Studio version, [platform] is e.g. x64 and
56 [type] Native of Cross platform build. This type of command prompt may not
57 exist in all Visual Studio versions.
58
59 See also: [Set the Path and Environment Variables for Command-Line Builds](https://msdn.microsoft.com/en-us/library/f2ccy3wt.aspx)
60
61## Build in the console
62
63 Once you are in the console, go to the winbuild directory in the Curl
64 sources:
65
66 cd curl-src\winbuild
67
68 Then you can call `nmake /f Makefile.vc` with the desired options (see
69 below). The builds will be in the top src directory, `builds\` directory, in
70 a directory named using the options given to the nmake call.
71
72 nmake /f Makefile.vc mode=<static or dll> <options>
73
74where `<options>` is one or many of:
75
76 - `VC=<num>` - VC version. 6 or later.
77 - `WITH_DEVEL=<path>` - Paths for the development files (SSL, zlib, etc.)
78 Defaults to sibbling directory deps: ../deps
79 Libraries can be fetched at https://windows.php.net/downloads/php-sdk/deps/
80 Uncompress them into the deps folder.
81 - `WITH_SSL=<dll/static>` - Enable OpenSSL support, DLL or static
82 - `WITH_NGHTTP2=<dll/static>` - Enable HTTP/2 support, DLL or static
83 - `WITH_MBEDTLS=<dll/static>` - Enable mbedTLS support, DLL or static
84 - `WITH_CARES=<dll/static>` - Enable c-ares support, DLL or static
85 - `WITH_ZLIB=<dll/static>` - Enable zlib support, DLL or static
86 - `WITH_SSH2=<dll/static>` - Enable libSSH2 support, DLL or static
87 - `WITH_PREFIX=<dir>` - Where to install the build
88 - `ENABLE_SSPI=<yes/no>` - Enable SSPI support, defaults to yes
89 - `ENABLE_IPV6=<yes/no>` - Enable IPv6, defaults to yes
90 - `ENABLE_IDN=<yes or no>` - Enable use of Windows IDN APIs, defaults to yes
91 Requires Windows Vista or later
92 - `ENABLE_SCHANNEL=<yes/no>` - Enable native Windows SSL support, defaults
93 to yes if SSPI and no other SSL library
94 - `ENABLE_OPENSSL_AUTO_LOAD_CONFIG=<yes/no>`
95 - Enable loading OpenSSL configuration
96 automatically, defaults to yes
97 - `ENABLE_UNICODE=<yes/no>` - Enable UNICODE support, defaults to no
98 - `GEN_PDB=<yes/no>` - Generate External Program Database
99 (debug symbols for release build)
100 - `DEBUG=<yes/no>` - Debug builds
101 - `MACHINE=<x86/x64>` - Target architecture (default is x86)
102 - `CARES_PATH=<path>` - Custom path for c-ares
103 - `MBEDTLS_PATH=<path>` - Custom path for mbedTLS
104 - `NGHTTP2_PATH=<path>` - Custom path for nghttp2
105 - `SSH2_PATH=<path>` - Custom path for libSSH2
106 - `SSL_PATH=<path>` - Custom path for OpenSSL
107 - `ZLIB_PATH=<path>` - Custom path for zlib
108
109## Static linking of Microsoft's C RunTime (CRT):
110
111 If you are using mode=static nmake will create and link to the static build
112 of libcurl but *not* the static CRT. If you must you can force nmake to link
113 in the static CRT by passing RTLIBCFG=static. Typically you shouldn't use
114 that option, and nmake will default to the DLL CRT. RTLIBCFG is rarely used
115 and therefore rarely tested. When passing RTLIBCFG for a configuration that
116 was already built but not with that option, or if the option was specified
117 differently, you must destroy the build directory containing the
118 configuration so that nmake can build it from scratch.
119
120## Building your own application with a static libcurl
121
122 When building an application that uses the static libcurl library on Windows,
123 you must define CURL_STATICLIB. Otherwise the linker will look for dynamic
124 import symbols.
125
126## Legacy Windows and SSL
127
128 When you build curl using the build files in this directory the default SSL
129 backend will be Schannel (Windows SSPI), the native SSL library that comes
130 with the Windows OS. Schannel in Windows <= XP is not able to connect to
131 servers that no longer support the legacy handshakes and algorithms used by
132 those versions. If you will be using curl in one of those earlier versions of
133 Windows you should choose another SSL backend like OpenSSL.
134