5 This document describes installation on all supported operating
6 systems (the Linux/Unix family, OpenVMS and Windows)
8 To install OpenSSL, you will need:
10 * A make implementation
11 * Perl 5 with core modules (please read NOTES.PERL)
12 * The perl module Text::Template (please read NOTES.PERL)
14 * a development environment in the form of development libraries and C
16 * a supported operating system
18 For additional platform specific requirements, solutions to specific
19 issues and other details, please read one of these:
21 * NOTES.UNIX (any supported Unix like system)
23 * NOTES.WIN (any supported Windows)
24 * NOTES.DJGPP (DOS platform with DJGPP)
26 Notational conventions in this document
27 ---------------------------------------
29 Throughout this document, we use the following conventions in command
32 $ command Any line starting with a dollar sign
33 ($) is a command line.
35 { word1 | word2 | word3 } This denotes a mandatory choice, to be
36 replaced with one of the given words.
37 A simple example would be this:
39 $ echo { FOO | BAR | COOKIE }
41 which is to be understood as one of
50 [ word1 | word2 | word3 ] Similar to { word1 | word2 | word3 }
51 except it's optional to give any of
52 those. In addition to the examples
53 above, this would also be valid:
57 {{ target }} This denotes a mandatory word or
58 sequence of words of some sort. A
59 simple example would be this:
63 which is to be understood to use the
64 command 'type' on some file name
65 determined by the user.
67 [[ options ]] Similar to {{ target }}, but is
70 Note that the notation assumes spaces around {, }, [, ], {{, }} and
71 [[, ]]. This is to differentiate from OpenVMS directory
72 specifications, which also use [ and ], but without spaces.
77 If you want to just get on with it, do:
93 on Windows (only pick one of the targets for configuration):
95 $ perl Configure { VC-WIN32 | VC-WIN64A | VC-WIN64I | VC-CE }
100 If any of these steps fails, see section Installation in Detail below.
102 This will build and install OpenSSL in the default location, which is:
104 Unix: normal installation directories under /usr/local
105 OpenVMS: SYS$COMMON:[OPENSSL-'version'...], where 'version' is the
106 OpenSSL version number with underscores instead of periods.
107 Windows: C:\Program Files\OpenSSL or C:\Program Files (x86)\OpenSSL
109 If you want to install it anywhere else, run config like this:
113 $ ./config --prefix=/opt/openssl --openssldir=/usr/local/ssl
117 $ @config --prefix=PROGRAM:[INSTALLS] --openssldir=SYS$MANAGER:[OPENSSL]
120 Configuration Options
121 ---------------------
123 There are several options to ./config (or ./Configure) to customize
124 the build (note that for Windows, the defaults for --prefix and
125 --openssldir depend in what configuration is used and what Windows
126 implementation OpenSSL is built on. More notes on this in NOTES.WIN):
129 Don't build with support for deprecated APIs below the
130 specified version number. For example "--api=1.1.0" will
131 remove support for all APIS that were deprecated in OpenSSL
132 version 1.1.0 or below.
134 --cross-compile-prefix=PREFIX
135 The PREFIX to include in front of commands for your
136 toolchain. It's likely to have to end with dash, e.g.
137 a-b-c- would invoke GNU compiler as a-b-c-gcc, etc.
138 Unfortunately cross-compiling is too case-specific to
139 put together one-size-fits-all instructions. You might
140 have to pass more flags or set up environment variables
141 to actually make it work. Android and iOS cases are
142 discussed in corresponding Configurations/10-main.cf
143 sections. But there are cases when this option alone is
144 sufficient. For example to build the mingw64 target on
145 Linux "--cross-compile-prefix=x86_64-w64-mingw32-"
146 works. Naturally provided that mingw packages are
147 installed. Today Debian and Ubuntu users have option to
148 install a number of prepackaged cross-compilers along
149 with corresponding run-time and development packages for
150 "alien" hardware. To give another example
151 "--cross-compile-prefix=mipsel-linux-gnu-" suffices
152 in such case. Needless to mention that you have to
153 invoke ./Configure, not ./config, and pass your target
157 Build OpenSSL with debugging symbols.
160 The name of the directory under the top of the installation
161 directory tree (see the --prefix option) where libraries will
162 be installed. By default this is "lib". Note that on Windows
163 only ".lib" files will be stored in this location. dll files
164 will always be installed to the "bin" directory.
167 Directory for OpenSSL configuration files, and also the
168 default certificate and key store. Defaults are:
171 Windows: C:\Program Files\Common Files\SSL
172 or C:\Program Files (x86)\Common Files\SSL
173 OpenVMS: SYS$COMMON:[OPENSSL-COMMON]
176 The top of the installation directory tree. Defaults are:
179 Windows: C:\Program Files\OpenSSL
180 or C:\Program Files (x86)\OpenSSL
181 OpenVMS: SYS$COMMON:[OPENSSL-'version']
184 Build OpenSSL without debugging symbols. This is the default.
187 This is a developer flag that switches on various compiler
188 options recommended for OpenSSL development. It only works
189 when using gcc or clang as the compiler. If you are
190 developing a patch for OpenSSL then it is recommended that
191 you use this option where possible.
193 --with-zlib-include=DIR
194 The directory for the location of the zlib include file. This
195 option is only necessary if enable-zlib (see below) is used
196 and the include file is not already on the system include
200 On Unix: this is the directory containing the zlib library.
201 If not provided the system library path will be used.
202 On Windows: this is the filename of the zlib library (with or
203 without a path). This flag must be provided if the
204 zlib-dynamic option is not also used. If zlib-dynamic is used
205 then this flag is optional and a default value ("ZLIB1") is
206 used if not provided.
207 On VMS: this is the filename of the zlib library (with or
208 without a path). This flag is optional and if not provided
209 then "GNV$LIBZSHR", "GNV$LIBZSHR32" or "GNV$LIBZSHR64" is
210 used by default depending on the pointer size chosen.
213 Don't build the AFALG engine. This option will be forced if
214 on a platform that does not support AFALG.
217 Build with the Address sanitiser. This is a developer option
218 only. It may not work on all platforms and should never be
219 used in production environments. It will only work when used
220 with gcc or clang and should be used in conjunction with the
224 Do not use assembler code. On some platforms a small amount
225 of assembler code may still be used.
228 Do not build support for async operations.
231 Don't automatically load all supported ciphers and digests.
232 Typically OpenSSL will make available all of its supported
233 ciphers and digests. For a statically linked application this
234 may be undesirable if small executable size is an objective.
235 This only affects libcrypto. Ciphers and digests will have to
236 be loaded manually using EVP_add_cipher() and
237 EVP_add_digest() if this option is used. This option will
238 force a non-shared build.
241 Don't automatically load all libcrypto/libssl error strings.
242 Typically OpenSSL will automatically load human readable
243 error strings. For a statically linked application this may
244 be undesirable if small executable size is an objective.
248 Don't build the CAPI engine. This option will be forced if
249 on a platform that does not support CAPI.
252 Don't build support for CMS features
255 Don't build support for SSL/TLS compression. If this option
256 is left enabled (the default), then compression will only
257 work if the zlib or zlib-dynamic options are also chosen.
260 Build support for debugging memory allocated via
261 OPENSSL_malloc() or OPENSSL_zalloc().
263 enable-crypto-mdebug-backtrace
264 As for crypto-mdebug, but additionally provide backtrace
265 information for allocated memory.
266 TO BE USED WITH CARE: this uses GNU C functionality, and
267 is therefore not usable for non-GNU config targets. If
268 your build complains about the use of '-rdynamic' or the
269 lack of header file execinfo.h, this option is not for you.
270 ALSO NOTE that even though execinfo.h is available on your
271 system (through Gnulib), the functions might just be stubs
275 Don't build support for Certificate Transparency.
278 Don't build with support for any deprecated APIs. This is the
279 same as using "--api" and supplying the latest version
283 Don't build support for datagram based BIOs. Selecting this
284 option will also force the disabling of DTLS.
287 Don't build support for loading Dynamic Shared Objects.
290 Don't build the dynamically loaded engines. This only has an
291 effect in a "shared" build
294 Don't build support for Elliptic Curves.
297 Don't build support for binary Elliptic Curves
299 enable-ec_nistp_64_gcc_128
300 Enable support for optimised implementations of some commonly
301 used NIST elliptic curves. This is only supported on some
305 Build support for gathering entropy from EGD (Entropy
309 Don't build support for loading engines.
312 Don't compile in any error strings.
315 Don't compile in filename and line number information (e.g.
316 for errors and memory allocation).
318 enable-fuzz-libfuzzer, enable-fuzz-afl
319 Build with support for fuzzing using either libfuzzer or AFL.
320 These are developer options only. They may not work on all
321 platforms and should never be used in production environments.
322 See the file fuzz/README.md for further details.
325 Don't build support for GOST based ciphersuites. Note that
326 if this feature is enabled then GOST ciphersuites are only
327 available if the GOST algorithms are also available through
328 loading an externally supplied engine.
331 Build support for DTLS heartbeats.
334 Don't build the padlock engine.
337 Don't generate dependencies.
340 Don't build support for writing multiple records in one
341 go in libssl (Note: this is a different capability to the
342 pipelining functionality).
345 Don't build support for the NPN TLS extension.
348 Don't build support for OCSP.
351 Don't build with support for Position Independent Code.
354 Don't use POSIX IO capabilities.
357 Don't build support for Pre-Shared Key based ciphersuites.
360 Don't use hardware RDRAND capabilities.
363 Don't build support for RFC3779 ("X.509 Extensions for IP
364 Addresses and AS Identifiers")
367 Build support for SCTP
370 Do not create shared libraries, only static ones. See "Note
371 on shared libraries" below.
374 Don't build support for socket BIOs
377 Don't build support for SRP or SRP based ciphersuites.
380 Don't build SRTP support
383 Exclude SSE2 code paths from 32-bit x86 assembly modules.
384 Normally SSE2 extension is detected at run-time, but the
385 decision whether or not the machine code will be executed
386 is taken solely on CPU capability vector. This means that
387 if you happen to run OS kernel which does not support SSE2
388 extension on Intel P4 processor, then your application
389 might be exposed to "illegal instruction" exception.
390 There might be a way to enable support in kernel, e.g.
391 FreeBSD kernel can be compiled with CPU_ENABLE_SSE, and
392 there is a way to disengage SSE2 code paths upon application
393 start-up, but if you aim for wider "audience" running
394 such kernel, consider no-sse2. Both the 386 and
395 no-asm options imply no-sse2.
398 Build with the SSL Trace capabilities (adds the "-trace"
399 option to s_client and s_server).
402 Don't build the statically linked engines. This only
403 has an impact when not built "shared".
406 Don't use any C "stdio" features. Only libcrypto and libssl
407 can be built in this way. Using this option will suppress
408 building the command line applications. Additionally since
409 the OpenSSL tests also use the command line applications the
410 tests will also be skipped.
413 Don't try to build with support for multi-threaded
417 Build with support for multi-threaded applications. Most
418 platforms will enable this by default. However if on a
419 platform where this is not the case then this will usually
420 require additional system-dependent options! See "Note on
421 multi-threading" below.
424 Don't build Time Stamping Authority support.
427 Build with the Undefined Behaviour sanitiser. This is a
428 developer option only. It may not work on all platforms and
429 should never be used in production environments. It will only
430 work when used with gcc or clang and should be used in
431 conjunction with the "-DPEDANTIC" option (or the
432 --strict-warnings option).
435 Don't build with the "UI" capability (i.e. the set of
436 features enabling text based prompts).
439 Enable additional unit test APIs. This should not typically
440 be used in production deployments.
442 enable-weak-ssl-ciphers
443 Build support for SSL/TLS ciphers that are considered "weak"
444 (e.g. RC4 based ciphersuites).
447 Build with support for zlib compression/decompression.
450 Like "zlib", but has OpenSSL load the zlib library
451 dynamically when needed. This is only supported on systems
452 where loading of shared libraries is supported.
455 In 32-bit x86 builds, when generating assembly modules,
456 use the 80386 instruction set only (the default x86 code
457 is more efficient, but requires at least a 486). Note:
458 This doesn't affect code generated by compiler, you're
459 likely to complement configuration command line with
460 suitable compiler-specific option.
463 Don't build support for negotiating the specified SSL/TLS
464 protocol (one of ssl, ssl3, tls, tls1, tls1_1, tls1_2, dtls,
465 dtls1 or dtls1_2). If "no-tls" is selected then all of tls1,
466 tls1_1 and tls1_2 are disabled. Similarly "no-dtls" will
467 disable dtls1 and dtls1_2. The "no-ssl" option is synonymous
468 with "no-ssl3". Note this only affects version negotiation.
469 OpenSSL will still provide the methods for applications to
470 explicitly select the individual protocol versions.
473 As for no-<prot> but in addition do not build the methods for
474 applications to explicitly select individual protocol
478 Build with support for the specified algorithm, where <alg>
479 is one of: md2 or rc5.
482 Build without support for the specified algorithm, where
483 <alg> is one of: bf, blake2, camellia, cast, chacha, cmac,
484 des, dh, dsa, ecdh, ecdsa, idea, md4, mdc2, ocb, poly1305,
485 rc2, rc4, rmd160, scrypt, seed or whirlpool. The "ripemd"
486 algorithm is deprecated and if used is synonymous with rmd160.
488 -Dxxx, -lxxx, -Lxxx, -fxxx, -mXXX, -Kxxx
489 These system specific options will be passed through to the
490 compiler to allow you to define preprocessor symbols, specify
491 additional libraries, library directories or other compiler
492 options. It might be worth noting that some compilers
493 generate code specifically for processor the compiler
494 currently executes on. This is not necessarily what you might
495 have in mind, since it might be unsuitable for execution on
496 other, typically older, processor. Consult your compiler
500 Installation in Detail
501 ----------------------
503 1a. Configure OpenSSL for your operation system automatically:
505 NOTE: This is not available on Windows.
507 $ ./config [[ options ]] # Unix
511 $ @config [[ options ]] ! OpenVMS
513 For the remainder of this text, the Unix form will be used in all
514 examples, please use the appropriate form for your platform.
516 This guesses at your operating system (and compiler, if necessary) and
517 configures OpenSSL based on this guess. Run ./config -t to see
518 if it guessed correctly. If you want to use a different compiler, you
519 are cross-compiling for another platform, or the ./config guess was
520 wrong for other reasons, go to step 1b. Otherwise go to step 2.
522 On some systems, you can include debugging information as follows:
524 $ ./config -d [[ options ]]
526 1b. Configure OpenSSL for your operating system manually
528 OpenSSL knows about a range of different operating system, hardware and
529 compiler combinations. To see the ones it knows about, run
535 $ perl Configure # All other platforms
537 For the remainder of this text, the Unix form will be used in all
538 examples, please use the appropriate form for your platform.
540 Pick a suitable name from the list that matches your system. For most
541 operating systems there is a choice between using "cc" or "gcc". When
542 you have identified your system (and if necessary compiler) use this name
543 as the argument to Configure. For example, a "linux-elf" user would
546 $ ./Configure linux-elf [[ options ]]
548 If your system isn't listed, you will have to create a configuration
549 file named Configurations/{{ something }}.conf and add the correct
550 configuration for your system. See the available configs as examples
551 and read Configurations/README and Configurations/README.design for
554 The generic configurations "cc" or "gcc" should usually work on 32 bit
557 Configure creates a build file ("Makefile" on Unix, "makefile" on Windows
558 and "descrip.mms" on OpenVMS) from a suitable template in Configurations,
559 and defines various macros in include/openssl/opensslconf.h (generated from
560 include/openssl/opensslconf.h.in).
562 1c. Configure OpenSSL for building outside of the source tree.
564 OpenSSL can be configured to build in a build directory separate from
565 the directory with the source code. It's done by placing yourself in
566 some other directory and invoking the configuration commands from
571 $ mkdir /var/tmp/openssl-build
572 $ cd /var/tmp/openssl-build
573 $ /PATH/TO/OPENSSL/SOURCE/config [[ options ]]
577 $ /PATH/TO/OPENSSL/SOURCE/Configure {{ target }} [[ options ]]
581 $ set default sys$login:
582 $ create/dir [.tmp.openssl-build]
583 $ set default [.tmp.openssl-build]
584 $ @[PATH.TO.OPENSSL.SOURCE]config [[ options ]]
588 $ @[PATH.TO.OPENSSL.SOURCE]Configure {{ target }} [[ options ]]
593 $ mkdir \temp-openssl
595 $ perl d:\PATH\TO\OPENSSL\SOURCE\Configure {{ target }} [[ options ]]
597 Paths can be relative just as well as absolute. Configure will
598 do its best to translate them to relative paths whenever possible.
600 2. Build OpenSSL by running:
603 $ mms ! (or mmk) OpenVMS
606 This will build the OpenSSL libraries (libcrypto.a and libssl.a on
607 Unix, corresponding on other platforms) and the OpenSSL binary
608 ("openssl"). The libraries will be built in the top-level directory,
609 and the binary will be in the "apps" subdirectory.
611 If the build fails, look at the output. There may be reasons
612 for the failure that aren't problems in OpenSSL itself (like
613 missing standard headers). If you are having problems you can
614 get help by sending an email to the openssl-users email list (see
615 https://www.openssl.org/community/mailinglists.html for details). If
616 it is a bug with OpenSSL itself, please open an issue on GitHub, at
617 https://github.com/openssl/openssl/issues. Please review the existing
618 ones first; maybe the bug was already reported or has already been
621 (If you encounter assembler error messages, try the "no-asm"
622 configuration option as an immediate fix.)
624 Compiling parts of OpenSSL with gcc and others with the system
625 compiler will result in unresolved symbols on some systems.
627 3. After a successful build, the libraries should be tested. Run:
631 $ nmake test # Windows
633 NOTE: you MUST run the tests from an unprivileged account (or
634 disable your privileges temporarily if your platform allows it).
636 If some tests fail, look at the output. There may be reasons for
637 the failure that isn't a problem in OpenSSL itself (like a
638 malfunction with Perl). You may want increased verbosity, that
639 can be accomplished like this:
641 $ make VERBOSE=1 test # Unix
643 $ mms /macro=(VERBOSE=1) test ! OpenVMS
645 $ nmake VERBOSE=1 test # Windows
647 If you want to run just one or a few specific tests, you can use
648 the make variable TESTS to specify them, like this:
650 $ make TESTS='test_rsa test_dsa' test # Unix
651 $ mms/macro="TESTS=test_rsa test_dsa" test ! OpenVMS
652 $ nmake TESTS='test_rsa test_dsa' test # Windows
654 And of course, you can combine (Unix example shown):
656 $ make VERBOSE=1 TESTS='test_rsa test_dsa' test
658 You can find the list of available tests like this:
660 $ make list-tests # Unix
661 $ mms list-tests ! OpenVMS
662 $ nmake list-tests # Windows
664 Have a look at the manual for the perl module Test::Harness to
665 see what other HARNESS_* variables there are.
667 If you find a problem with OpenSSL itself, try removing any
668 compiler optimization flags from the CFLAGS line in Makefile and
669 run "make clean; make" or corresponding.
671 Please send bug reports to <rt@openssl.org>.
673 4. If everything tests ok, install OpenSSL with
675 $ make install # Unix
676 $ mms install ! OpenVMS
677 $ nmake install # Windows
679 This will install all the software components in this directory
680 tree under PREFIX (the directory given with --prefix or its
685 bin/ Contains the openssl binary and a few other
688 Contains the header files needed if you want
689 to build your own programs that use libcrypto
691 lib Contains the OpenSSL library files.
692 lib/engines Contains the OpenSSL dynamically loadable engines.
694 share/man/man1 Contains the OpenSSL command line man-pages.
695 share/man/man3 Contains the OpenSSL library calls man-pages.
696 share/man/man5 Contains the OpenSSL configuration format man-pages.
697 share/man/man7 Contains the OpenSSL other misc man-pages.
699 share/doc/openssl/html/man1
700 share/doc/openssl/html/man3
701 share/doc/openssl/html/man5
702 share/doc/openssl/html/man7
703 Contains the HTML rendition of the man-pages.
705 OpenVMS ('arch' is replaced with the architecture name, "Alpha"
706 or "ia64", 'sover' is replaced with the shared library version
707 (0101 for 1.1), and 'pz' is replaced with the pointer size
708 OpenSSL was built with):
710 [.EXE.'arch'] Contains the openssl binary.
711 [.EXE] Contains a few utility scripts.
713 Contains the header files needed if you want
714 to build your own programs that use libcrypto
716 [.LIB.'arch'] Contains the OpenSSL library files.
717 [.ENGINES'sover''pz'.'arch']
718 Contains the OpenSSL dynamically loadable engines.
719 [.SYS$STARTUP] Contains startup, login and shutdown scripts.
720 These define appropriate logical names and
722 [.SYSTEST] Contains the installation verification procedure.
723 [.HTML] Contains the HTML rendition of the manual pages.
726 Additionally, install will add the following directories under
727 OPENSSLDIR (the directory given with --openssldir or its default)
730 certs Initially empty, this is the default location
731 for certificate files.
732 private Initially empty, this is the default location
733 for private key files.
734 misc Various scripts.
736 Package builders who want to configure the library for standard
737 locations, but have the package installed somewhere else so that
738 it can easily be packaged, can use
740 $ make DESTDIR=/tmp/package-root install # Unix
741 $ mms/macro="DESTDIR=TMP:[PACKAGE-ROOT]" install ! OpenVMS
743 The specified destination directory will be prepended to all
744 installation target paths.
746 Compatibility issues with previous OpenSSL versions:
748 * COMPILING existing applications
750 OpenSSL 1.1.0 hides a number of structures that were previously
751 open. This includes all internal libssl structures and a number
752 of EVP types. Accessor functions have been added to allow
753 controlled access to the structures' data.
755 This means that some software needs to be rewritten to adapt to
756 the new ways of doing things. This often amounts to allocating
757 an instance of a structure explicitly where you could previously
758 allocate them on the stack as automatic variables, and using the
759 provided accessor functions where you would previously access a
760 structure's field directly.
762 Some APIs have changed as well. However, older APIs have been
763 preserved when possible.
765 Environment Variables
766 ---------------------
768 A number of environment variables can be used to provide additional control
769 over the build process. Typically these should be defined prior to running
770 config or Configure. Not all environment variables are relevant to all
774 The name of the ar executable to use.
777 Use a different build file name than the platform default
778 ("Makefile" on Unixly platforms, "makefile" on native Windows,
779 "descrip.mms" on OpenVMS). This requires that there is a
780 corresponding build file template. See Configurations/README
781 for further information.
784 The compiler to use. Configure will attempt to pick a default
785 compiler for your platform but this choice can be overridden
786 using this variable. Set it to the compiler executable you wish
787 to use, e.g. "gcc" or "clang".
790 This environment variable has the same meaning as for the
791 "--cross-compile-prefix" Configure flag described above. If both
792 are set then the Configure flag takes precedence.
795 The name of the nm executable to use.
797 OPENSSL_LOCAL_CONFIG_DIR
798 OpenSSL comes with a database of information about how it
799 should be built on different platforms as well as build file
800 templates for those platforms. The database is comprised of
801 ".conf" files in the Configurations directory. The build
802 file templates reside there as well as ".tmpl" files. See the
803 file Configurations/README for further information about the
804 format of ".conf" files as well as information on the ".tmpl"
806 In addition to the standard ".conf" and ".tmpl" files, it is
807 possible to create your own ".conf" and ".tmpl" files and store
808 them locally, outside the OpenSSL source tree. This environment
809 variable can be set to the directory where these files are held
810 and will have Configure to consider them in addition to the
814 The name of the Perl executable to use when building OpenSSL.
817 The command string for the Perl executable to insert in the
818 #! line of perl scripts that will be publically installed.
819 Default: /usr/bin/env perl
820 Note: the value of this variable is added to the same scripts
821 on all platforms, but it's only relevant on Unix-like platforms.
824 The name of the rc executable to use. The default will be as
825 defined for the target platform in the ".conf" file. If not
826 defined then "windres" will be used. The WINDRES environment
827 variable is synonymous to this. If both are defined then RC
831 The name of the ranlib executable to use.
839 The Configure script generates a Makefile in a format relevant to the specific
840 platform. The Makefiles provide a number of targets that can be used. Not all
841 targets may be available on all platforms. Only the most common targets are
842 described here. Examine the Makefiles themselves for the full list.
845 The default target to build all the software components.
848 Remove all build artefacts and return the directory to a "clean"
852 Rebuild the dependencies in the Makefiles. This is a legacy
853 option that no longer needs to be used in OpenSSL 1.1.0.
856 Install all OpenSSL components.
859 Only install the OpenSSL software components.
862 Only install the OpenSSL documentation components.
865 Only install the OpenSSL man pages (Unix only).
868 Only install the OpenSSL html documentation.
871 Prints a list of all the self test names.
874 Build and run the OpenSSL self tests.
877 Uninstall all OpenSSL components.
880 This is a developer option. If you are developing a patch for
881 OpenSSL you may need to use this if you want to update
882 automatically generated files; add new error codes or add new
883 (or change the visibility of) public API functions. (Unix only).
885 Note on multi-threading
886 -----------------------
888 For some systems, the OpenSSL Configure script knows what compiler options
889 are needed to generate a library that is suitable for multi-threaded
890 applications. On these systems, support for multi-threading is enabled
891 by default; use the "no-threads" option to disable (this should never be
894 On other systems, to enable support for multi-threading, you will have
895 to specify at least two options: "threads", and a system-dependent option.
896 (The latter is "-D_REENTRANT" on various systems.) The default in this
897 case, obviously, is not to include support for multi-threading (but
898 you can still use "no-threads" to suppress an annoying warning message
899 from the Configure script.)
901 OpenSSL provides built-in support for two threading models: pthreads (found on
902 most UNIX/Linux systems), and Windows threads. No other threading models are
903 supported. If your platform does not provide pthreads or Windows threads then
904 you should Configure with the "no-threads" option.
906 Notes on shared libraries
907 -------------------------
909 For most systems the OpenSSL Configure script knows what is needed to
910 build shared libraries for libcrypto and libssl. On these systems
911 the shared libraries will be created by default. This can be suppressed and
912 only static libraries created by using the "no-shared" option. On systems
913 where OpenSSL does not know how to build shared libraries the "no-shared"
914 option will be forced and only static libraries will be created.
916 Shared libraries are named a little differently on different platforms.
917 One way or another, they all have the major OpenSSL version number as
918 part of the file name, i.e. for OpenSSL 1.1.x, 1.1 is somehow part of
921 On most POSIXly platforms, shared libraries are named libcrypto.so.1.1
924 on Cygwin, shared libraries are named cygcrypto-1.1.dll and cygssl-1.1.dll
925 with import libraries libcrypto.dll.a and libssl.dll.a.
927 On Windows build with MSVC or using MingW, shared libraries are named
928 libcrypto-1_1.dll and libssl-1_1.dll for 32-bit Windows, libcrypto-1_1-x64.dll
929 and libssl-1_1-x64.dll for 64-bit x86_64 Windows, and libcrypto-1_1-ia64.dll
930 and libssl-1_1-ia64.dll for IA64 Windows. With MSVC, the import libraries
931 are named libcrypto.lib and libssl.lib, while with MingW, they are named
932 libcrypto.dll.a and libssl.dll.a.
934 On VMS, shareable images (VMS speak for shared libraries) are named
935 ossl$libcrypto0101_shr.exe and ossl$libssl0101_shr.exe. However, when
936 OpenSSL is specifically built for 32-bit pointers, the shareable images
937 are named ossl$libcrypto0101_shr32.exe and ossl$libssl0101_shr32.exe
938 instead, and when built for 64-bit pointers, they are named
939 ossl$libcrypto0101_shr64.exe and ossl$libssl0101_shr64.exe.
941 Note on random number generation
942 --------------------------------
944 Availability of cryptographically secure random numbers is required for
945 secret key generation. OpenSSL provides several options to seed the
946 internal PRNG. If not properly seeded, the internal PRNG will refuse
947 to deliver random bytes and a "PRNG not seeded error" will occur.
948 On systems without /dev/urandom (or similar) device, it may be necessary
949 to install additional support software to obtain a random seed.
950 Please check out the manual pages for RAND_add(), RAND_bytes(), RAND_egd(),
951 and the FAQ for more information.
projects / openssl.git / blob