NOTES FOR THE WINDOWS PLATFORMS =============================== Windows targets can be classified as "native", ones that use Windows API directly, and "hosted" which rely on POSIX-compatible layer. "Native" targets are VC-* (where "VC" stems from abbreviating Microsoft Visual C compiler) and mingw[64]. "Hosted" platforms are Cygwin and MSYS[2]. Even though the latter is not directly supported by OpenSSL Team, it's #1 popular choice for building MinGW targets. In the nutshell MinGW builds are always cross-compiled. On Linux and Cygwin they look exactly as such and require --cross-compile-prefix option. While on MSYS[2] it's solved rather by placing gcc that produces "MinGW binary" code 1st on $PATH. This is customarily source of confusion. "Hosted" applications "live" in emulated file system name space with POSIX-y root, mount points, /dev and even /proc. Confusion is intensified by the fact that MSYS2 shell (or rather emulated execve(2) call) examines the binary it's about to start, and if it's found *not* to be linked with MSYS2 POSIX-y thing, command line arguments that look like file names get translated from emulated name space to "native". For example '/c/some/where' becomes 'c:\some\where', '/dev/null' - 'nul'. This creates an illusion that there is no difference between MSYS2 shell and "MinGW binary", but there is. Just keep in mind that "MinGW binary" "experiences" Windows system in exactly same way as one produced by VC, and in its essence is indistinguishable from the latter. (Which by the way is why it's referred to in quotes here, as "MinGW binary", it's just as "native" as it can get.) Visual C++ builds, a.k.a. VC-* ============================== Requirement details ------------------- In addition to the requirements and instructions listed in INSTALL, these are required as well: - Perl. We recommend ActiveState Perl, available from https://www.activestate.com/ActivePerl. Another viable alternative appears to be Strawberry Perl, http://strawberryperl.com. You also need the perl module Text::Template, available on CPAN. Please read NOTES.PERL for more information. - Microsoft Visual C compiler. Since we can't test them all, there is unavoidable uncertainty about which versions are supported. Latest version along with couple of previous are certainly supported. On the other hand oldest one is known not to work. Everything between falls into best-effort category. - Netwide Assembler, a.k.a. NASM, available from https://www.nasm.us, is required. Note that NASM is the only supported assembler. Even though Microsoft provided assembler is NOT supported, contemporary 64-bit version is exercised through continuous integration of VC-WIN64A-masm target. Installation directories ------------------------ The default installation directories are derived from environment variables. For VC-WIN32, the following defaults are use: PREFIX: %ProgramFiles(86)%\OpenSSL OPENSSLDIR: %CommonProgramFiles(86)%\SSL For VC-WIN64, the following defaults are use: PREFIX: %ProgramW6432%\OpenSSL OPENSSLDIR: %CommonProgramW6432%\SSL Should those environment variables not exist (on a pure Win32 installation for examples), these fallbacks are used: PREFIX: %ProgramFiles%\OpenSSL OPENSSLDIR: %CommonProgramFiles%\SSL ALSO NOTE that those directories are usually write protected, even if your account is in the Administrators group. To work around that, start the command prompt by right-clicking on it and choosing "Run as Administrator" before running 'nmake install'. The other solution is, of course, to choose a different set of directories by using --prefix and --openssldir when configuring. mingw and mingw64 ================= * MSYS2 shell and development environment installation: Download MSYS2 from https://msys2.github.io/ and follow installation instructions. Once up and running install even make, perl, (git if needed,) mingw-w64-i686-gcc and/or mingw-w64-x86_64-gcc. You should have corresponding MinGW items on your start menu, use *them*, not generic MSYS2. As implied in opening note, difference between them is which compiler is found 1st on $PATH. At this point ./config should recognize correct target, roll as if it was Unix... * It is also possible to build mingw[64] on Linux or Cygwin by configuring with corresponding --cross-compile-prefix= option. For example ./Configure mingw --cross-compile-prefix=i686-w64-mingw32- ... or ./Configure mingw64 --cross-compile-prefix=x86_64-w64-mingw32- ... This naturally implies that you've installed corresponding add-on packages. Linking your application ======================== This section applies to all "native" builds. If you link with static OpenSSL libraries then you're expected to additionally link your application with WS2_32.LIB, GDI32.LIB, ADVAPI32.LIB, CRYPT32.LIB and USER32.LIB. Those developing non-interactive service applications might feel concerned about linking with GDI32.LIB and USER32.LIB, as they are justly associated with interactive desktop, which is not available to service processes. The toolkit is designed to detect in which context it's currently executed, GUI, console app or service, and act accordingly, namely whether or not to actually make GUI calls. Additionally those who wish to /DELAYLOAD:GDI32.DLL and /DELAYLOAD:USER32.DLL and actually keep them off service process should consider implementing and exporting from .exe image in question own _OPENSSL_isservice not relying on USER32.DLL. E.g., on Windows Vista and later you could: __declspec(dllexport) __cdecl BOOL _OPENSSL_isservice(void) { DWORD sess; if (ProcessIdToSessionId(GetCurrentProcessId(),&sess)) return sess==0; return FALSE; } If you link with OpenSSL .DLLs, then you're expected to include into your application code small "shim" snippet, which provides glue between OpenSSL BIO layer and your compiler run-time. See the OPENSSL_Applink manual page for further details. Cygwin, "hosted" environment ============================ Cygwin implements a Posix/Unix runtime system (cygwin1.dll) on top of the Windows subsystem and provides a bash shell and GNU tools environment. Consequently, a make of OpenSSL with Cygwin is virtually identical to the Unix procedure. To build OpenSSL using Cygwin, you need to: * Install Cygwin (see https://cygwin.com/) * Install Cygwin Perl and ensure it is in the path. Recall that as least 5.10.0 is required. * Run the Cygwin bash shell Apart from that, follow the Unix instructions in INSTALL. NOTE: "make test" and normal file operations may fail in directories mounted as text (i.e. mount -t c:\somewhere /home) due to Cygwin stripping of carriage returns. To avoid this ensure that a binary mount is used, e.g. mount -b c:\somewhere /home.