Building with Visual C++, prerequisites ======================================= This document describes how to compile, build and install curl and libcurl from sources using the Visual C++ build tool. To build with VC++, you will of course have to first install VC++. The minimum required version of VC is 6 (part of Visual Studio 6). However using a more recent version is strongly recommended. VC++ is also part of the Windows Platform SDK. You do not have to install the full Visual Studio or Visual C++ if all you want is to build curl. The latest Platform SDK can be downloaded freely from: https://developer.microsoft.com/en-us/windows/downloads/sdk-archive If you are building with VC6 then you will also need the February 2003 Edition of the Platform SDK which can be downloaded from: https://www.microsoft.com/en-us/download/details.aspx?id=12261 If you wish to support zlib, openssl, c-ares, ssh2, you will have to download them separately and copy them to the deps directory as shown below: somedirectory\ |_curl-src | |_winbuild | |_deps |_ lib |_ include |_ bin It is also possible to create the deps directory in some other random places and tell the Makefile its location using the WITH_DEVEL option. Building straight from git ========================== When you check out code git and build it, as opposed from a released source code archive, you need to first run the "buildconf.bat" batch file (present in the source code root directory) to set things up. Building with Visual C++ ======================== Open a Visual Studio Command prompt: Using the 'Developer Command Prompt for VS <version>' menu entry: where version is the Visual Studio version. The developer prompt at default uses the x86 mode. It is required to call Vcvarsall.bat to setup the prompt for the machine type you want, using Vcvarsall.bat. This type of command prompt may not exist in all Visual Studio versions. For more information, check: https://docs.microsoft.com/en-us/dotnet/framework/tools/developer-command-prompt-for-vs https://docs.microsoft.com/en-us/cpp/build/how-to-enable-a-64-bit-visual-cpp-toolset-on-the-command-line Using the 'VS <version> <platform> <type> Command Prompt' menu entry: where version is the Visual Studio version, platform is e.g. x64 and type Native of Cross platform build. This type of command prompt may not exist in all Visual Studio versions. See also: https://msdn.microsoft.com/en-us/library/f2ccy3wt.aspx Once you are in the console, go to the winbuild directory in the Curl sources: cd curl-src\winbuild Then you can call nmake /f Makefile.vc with the desired options (see below). The builds will be in the top src directory, builds\ directory, in a directory named using the options given to the nmake call. nmake /f Makefile.vc mode=<static or dll> <options> where <options> is one or many of: VC=<6,7,8,9,10,11,12,14,15> - VC versions WITH_DEVEL=<path> - Paths for the development files (SSL, zlib, etc.) Defaults to sibbling directory deps: ../deps Libraries can be fetched at http://windows.php.net/downloads/php-sdk/deps/ Uncompress them into the deps folder. WITH_SSL=<dll or static> - Enable OpenSSL support, DLL or static WITH_NGHTTP2=<dll or static> - Enable HTTP/2 support, DLL or static WITH_MBEDTLS=<dll or static> - Enable mbedTLS support, DLL or static WITH_CARES=<dll or static> - Enable c-ares support, DLL or static WITH_ZLIB=<dll or static> - Enable zlib support, DLL or static WITH_SSH2=<dll or static> - Enable libSSH2 support, DLL or static ENABLE_SSPI=<yes or no> - Enable SSPI support, defaults to yes ENABLE_IPV6=<yes or no> - Enable IPv6, defaults to yes ENABLE_IDN=<yes or no> - Enable use of Windows IDN APIs, defaults to yes Requires Windows Vista or later ENABLE_WINSSL=<yes or no> - Enable native Windows SSL support, defaults to yes GEN_PDB=<yes or no> - Generate Program Database (debug symbols for release build) DEBUG=<yes or no> - Debug builds MACHINE=<x86 or x64> - Target architecture (default is x86) CARES_PATH=<path to cares> - Custom path for c-ares MBEDTLS_PATH=<path to mbedTLS> - Custom path for mbedTLS NGHTTP2_PATH=<path to HTTP/2> - Custom path for nghttp2 SSH2_PATH=<path to libSSH2> - Custom path for libSSH2 SSL_PATH=<path to OpenSSL> - Custom path for OpenSSL ZLIB_PATH=<path to zlib> - Custom path for zlib Static linking of Microsoft's C RunTime (CRT): ============================================== If you are using mode=static nmake will create and link to the static build of libcurl but *not* the static CRT. If you must you can force nmake to link in the static CRT by passing RTLIBCFG=static. Typically you shouldn't use that option, and nmake will default to the DLL CRT. RTLIBCFG is rarely used and therefore rarely tested. When passing RTLIBCFG for a configuration that was already built but not with that option, or if the option was specified differently, you must destroy the build directory containing the configuration so that nmake can build it from scratch. Legacy Windows and SSL ====================== When you build curl using the build files in this directory the default SSL backend will be WinSSL (Windows SSPI, more specifically Schannel), the native SSL library that comes with the Windows OS. WinSSL in Windows <= XP is not able to connect to servers that no longer support the legacy handshakes and algorithms used by those versions. If you will be using curl in one of those earlier versions of Windows you should choose another SSL backend like OpenSSL.