
 NOTES FOR THE WINDOWS PLATFORMS
 ===============================

 Requirement details for native (Visual C++) builds
 --------------------------------------------------

 In addition to the requirements and instructions listed in INSTALL,
 these are required as well:

 - You need 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.

 - You need a C compiler.  OpenSSL has been tested to build with these:

   * Visual C++

 - Netwide Assembler, a.k.a. NASM, available from http://www.nasm.us,
   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-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.

 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 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.

 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 http://www.mingw.org/, 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 must be used.

   Alternatively, one can use MSYS2 from https://msys2.github.io/,
   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.
