NOTES FOR THE WINDOWS PLATFORMS =============================== [Notes for Windows CE can be found in INSTALL.WCE] Requirement details for native (Visual C++) builds -------------------------------------------------- - You need Perl. We recommend ActiveState Perl, available from You also need the perl module Text::Template, available on CPAN. Please read README.PERL for more information. - You need a C compiler. OpenSSL has been tested to build with these: * Visual C++ - Netwide Assembler, a.k.a. NASM, available from, is required if you intend to utilize assembler modules. Note that NASM is the only supported assembler. The Microsoft provided assembler is NOT supported. Visual C++ (native Windows) --------------------------- 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-WIN32, 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 GNU C (Cygwin) -------------- 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 * 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. It is also possible to create "conventional" Windows binaries that use the Microsoft C runtime system (msvcrt.dll or crtdll.dll) using MinGW development add-on for Cygwin. MinGW is supported even as a standalone setup as described in the following section. In the context you should recognize that binaries targeting Cygwin itself are not interchangeable with "conventional" Windows binaries you generate with/for MinGW. GNU C (MinGW/MSYS) ------------------ * Compiler and shell environment installation: MinGW and MSYS are available from, both are required. Run the installers and do whatever magic they say it takes to start MSYS bash shell with GNU tools and matching Perl on its PATH. "Matching Perl" refers to chosen "shell environment", i.e. if built under MSYS, then Perl compiled for MSYS is highly recommended. Alternativelly, one can use MSYS2 from, which includes MingW (32-bit and 64-bit). * It is also possible to cross-compile it on Linux by configuring with './Configure --cross-compile-prefix=i386-mingw32- mingw ...'. Other possible cross compile prefixes include x86_64-w64-mingw32- and i686-w64-mingw32-. Linking your application ------------------------ This section applies to non-Cygwin 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.