Home | History | Annotate | Line # | Download | only in dist
INSTALL revision 1.1.1.1.8.1
      1 Copyright 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013 Free Software Foundation, Inc.
      2 Contributed by the AriC and Caramel projects, INRIA.
      3 
      4 This file is part of the GNU MPFR Library.
      5 
      6 The GNU MPFR Library is free software; you can redistribute it and/or modify
      7 it under the terms of the GNU Lesser General Public License as published by
      8 the Free Software Foundation; either version 3 of the License, or (at your
      9 option) any later version.
     10 
     11 The GNU MPFR Library is distributed in the hope that it will be useful, but
     12 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
     13 or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
     14 License for more details.
     15 
     16 You should have received a copy of the GNU Lesser General Public License
     17 along with the GNU MPFR Library; see the file COPYING.LESSER.  If not, see
     18 http://www.gnu.org/licenses/ or write to the Free Software Foundation, Inc.,
     19 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.
     20 
     21 
     22 
     23                         Installing GNU MPFR
     24                         ===================
     25 
     26 Note: In case of problem, please read this INSTALL file carefully before
     27 reporting a bug, in particular Section "In case of problem" below. Some
     28 problems are due to bad configuration on the user side (not specific to
     29 MPFR).
     30 
     31 0. You first need to install GMP. See <http://www.gnu.org/software/gmp/>.
     32    MPFR requires GMP version 4.1 or later.
     33 
     34 1. Extract the files from the archive.
     35 
     36 2. It is strongly advised to apply the latest patches if this has
     37    not been done yet and if patches are available. You can check
     38    on the release page:
     39 
     40      http://www.mpfr.org/mpfr-3.1.2/
     41 
     42    which may have additional information. The patches can be applied
     43    with commands like:
     44 
     45      wget http://www.mpfr.org/mpfr-3.1.2/allpatches
     46      patch -N -Z -p1 < allpatches
     47 
     48    or
     49 
     50      curl http://www.mpfr.org/mpfr-3.1.2/allpatches | patch -N -Z -p1
     51 
     52    (Those instructions are for the GNU patch command, for example
     53    /usr/bin/gpatch on Solaris.)
     54 
     55 3. In the MPFR directory, to detect your system, type:
     56      ./configure
     57    possibly with options (see below, in particular if this step or
     58    one of the following fails). You should also check whether WARNING
     59    lines have been output (such a problem may cause a failure in one
     60    of the following steps).
     61    Note: paths provided in configure options must always be absolute
     62    (relative paths are not supported).
     63 
     64 4. To build the library, type:
     65      make
     66 
     67    [optional] if you want to tune MPFR for your specific architecture, see
     68    the section "Tuning MPFR" below. Note that for most common architectures,
     69    MPFR includes some default tuning parameters which should be near from
     70    optimal.
     71 
     72 5. To check the built library (runs the test files), type:
     73      make check
     74 
     75 6. To install it (default "/usr/local" | see "--prefix" option), type:
     76      make install
     77 
     78 If you installed MPFR (header and library) in directories that are
     79 not searched by default by the compiler and/or linking tools, then,
     80 like with other libraries, you may need to set up some environment
     81 variables such as C_INCLUDE_PATH (to find the header mpfr.h),
     82 LIBRARY_PATH (to find the library), and if the shared library has
     83 been installed, LD_LIBRARY_PATH (before execution) or LD_RUN_PATH
     84 (before linking); this list is not exhaustive and some environment
     85 variables may be specific to your system. "make install" gives some
     86 instructions; please read them. You can also find more information
     87 in the manuals of your compiler and linker. The MPFR FAQ may also
     88 give some information.
     89 
     90 Remember that if you have several MPFR (or GMP) versions installed
     91 (e.g., one with the system, and one, newer, by you), you will not
     92 necessarily get a compilation/linking error if a wrong library is
     93 used (e.g., because LD_LIBRARY_PATH has not been set correctly).
     94 But unexpected results may occur.
     95 
     96 Under Mac OS X, if the shared library was not installed and you use
     97 Apple's linker (this is the default), you will also need to provide
     98 the -search_paths_first linker flag ("-Wl,-search_paths_first" when
     99 you link via gcc) to make sure that the right library is selected,
    100 as by default, Apple's linker selects a shared library preferably,
    101 even when it is farther in the library paths. We recall that if a
    102 wrong library is selected due to this behavior, unexpected results
    103 may occur.
    104 
    105 
    106 Building the documentation
    107 ==========================
    108 
    109 To build the documentation in various formats, you may first need to
    110 install recent versions of some utilities such as texinfo.
    111 
    112 * Type "make info" to produce the documentation in the info format.
    113 
    114 * Type "make pdf" to produce the documentation in the PDF format.
    115 
    116 * Type "make dvi" to produce the documentation in the DVI format.
    117 
    118 * Type "make ps" to produce the documentation in the Postscript format.
    119 
    120 * Type "make html" to produce the documentation in the HTML format
    121   (in several pages); if you want only one output HTML file, then
    122   type "makeinfo --html --no-split mpfr.texi" from the doc directory
    123   instead.
    124 
    125 
    126 Building MPFR with internal GMP header files
    127 ============================================
    128 
    129 MPFR built with internal GMP header files is a bit faster, so you may want
    130 to build it with them. Just do this in step 1:
    131 
    132   ./configure --with-gmp-build=GMPBUILD
    133 
    134 where GMPBUILD is the GMP build directory. The needed header files are:
    135 gmp-impl.h, longlong.h and all the necessary headers to use them, which
    136 may be located either in the GMP source directory or in the GMP build
    137 directory, in case they are different (MPFR takes care of that, as of
    138 MPFR 3.1.0).
    139 
    140 Warning: the library obtained in this way may use some internal GMP
    141 symbols, and thus dynamically linking your software with a different
    142 version of GMP might fail, even though it is declared as compatible
    143 by Libtool's versioning system.
    144 
    145 
    146 Tuning MPFR
    147 ===========
    148 
    149 For this, you need to build MPFR with a GMP build directory (see above).
    150 In the GMP build directory, you also need to go into the "tune" subdirectory
    151 and type "make speed". This will build the GMP speed library, which is used
    152 by the MPFR tuning mechanism.
    153 
    154 Then go back to the MPFR build directory, go into the "tune" subdirectory and
    155 type "make tune". This will build an optimized file "mparam.h" for your
    156 specific architecture.
    157 
    158 
    159 ./configure options
    160 ===================
    161 
    162 --prefix=DIR            installs MPFR headers and library in DIR/include and
    163                         DIR/lib respectively (the default is "/usr/local").
    164 
    165 --with-gmp-include=DIR  assumes that DIR contains gmp.h
    166 --with-gmp-lib=DIR      assumes that DIR contains the GMP library
    167 --with-gmp=DIR          assumes that DIR is where you have installed GMP.
    168                         same as --with-gmp-lib=DIR/lib
    169                         and     --with-gmp-include=DIR/include
    170                         (use either --with-gmp alone or one or both of
    171                         --with-gmp-lib/--with-gmp-include)
    172                         Warning! Do not use these options if you have
    173                         CPPFLAGS and/or LDFLAGS containing a -I or -L
    174                         option with a directory that contains a GMP
    175                         header or library file, as these options just
    176                         add -I and -L options to CPPFLAGS and LDFLAGS
    177                         *after* the ones that are currently declared,
    178                         so that DIR will have a lower precedence. Also,
    179                         this may not work if DIR is a system directory
    180                         (typically /usr or /usr/local); see below.
    181 
    182 --with-gmp-build=DIR    assumes that DIR contains the GMP build directory,
    183                         and enables the use of GMP internals (see above).
    184                         Warning! This option and the group of options
    185                         --with-gmp are mutually exclusive.
    186 
    187 --enable-assert         build MPFR with assertions.
    188 
    189 --enable-thread-safe    build MPFR as thread safe, using compiler-level
    190                         Thread Local Storage (TLS). Note: TLS support is
    191                         roughly tested by configure. If configure detects
    192                         that TLS does not work (because of the compiler,
    193                         linker or system libraries), it will output an
    194                         error message, telling you to build MPFR without
    195                         thread safe. For instance, though Mac OS X uses
    196                         GCC, it may not currently support GCC's __thread
    197                         storage class.
    198 
    199 --disable-thread-safe   build MPFR without TLS. By default, TLS support
    200                         is detected automatically, and MPFR is built as
    201                         thread safe if supported. However this detection
    202                         is only a heuristic: TLS can be detected as
    203                         supported while its support is incomplete or
    204                         buggy (MPFR tests may fail). In such a case,
    205                         this option is useful.
    206 
    207 --enable-gmp-internals  allows the MPFR build to use GMP's undocumented
    208                         functions (not from the public API). Note that
    209                         library versioning is not guaranteed to work if
    210                         this option is used. Thus it must not be used in
    211                         binary distributions.
    212 
    213 Note: By default, the configure script tries to set CC/CFLAGS to GMP's
    214 ones (this feature needs GMP 4.3.0 or later, or the --with-gmp-build
    215 option). However this is not guaranteed to work as the configure script
    216 does some compiler tests earlier, and the change may be too late. Also,
    217 the values obtained from GMP may be incorrect if GMP has been built
    218 on a different machine. In such a case, the user may need to specify
    219 CC/CFLAGS as explained below.
    220 
    221 Run "./configure --help" to see the other options (autoconf default options).
    222 
    223 
    224 If 'gmp.h' and 'libgmp' do not match
    225 ====================================
    226 
    227 Under some circumstances, the configure script may output a message
    228 saying:
    229 
    230   'gmp.h' and 'libgmp' seem to have different versions or
    231   we cannot run a program linked with GMP (if you cannot
    232   see the version numbers above). [...]
    233 
    234 Even though the configure script does not fail in such a case, this
    235 message most often indicates a real error, which needs to be avoided.
    236 Possible causes are:
    237 
    238 * The wanted GMP library does not have the same ABI as the one chosen
    239   to build MPFR. The consequences may be:
    240 
    241     - A different GMP library (with the correct ABI) has been found,
    242       but does not have the same version as 'gmp.h'.
    243 
    244     - No other GMP libraries have been found (in this case, no version
    245       numbers should be printed above the warning message).
    246 
    247   This is incorrect and one of the following steps (make, make check)
    248   will probably fail. GMP (actually gmp.h) now provides CC and CFLAGS
    249   information to select the correct ABI, so that this problem should
    250   no longer occur; but if GMP was provided by a binary package, such
    251   information may not be valid. See the
    252 
    253     checking for CC and CFLAGS in gmp.h...
    254 
    255   line in the configure output (about the 11th line) and the following
    256   few ones for more information. You may need to reinstall GMP or to
    257   provide your own CC and/or CFLAGS. See also the remaining of this
    258   INSTALL file.
    259 
    260 * A configure option like --with-gmp or --with-gmp-include was used
    261   with a system include directory, e.g. one of the following:
    262 
    263     --with-gmp=/usr
    264     --with-gmp=/usr/local
    265     --with-gmp-include=/usr/include
    266     --with-gmp-include=/usr/local/include
    267 
    268   GCC (and possibly other compilers) will ignore such a directive for
    269   include directories (but this rule is not applied for the library
    270   itself!). This means that the library search paths will be reordered
    271   as declared, but the specified include directory will still be near
    272   the end of the include search paths (thus with a low precedence).
    273   This is not a problem if only one GMP version is installed, but
    274   otherwise, a wrong gmp.h may be chosen, so that the versions of
    275   gmp.h and libgmp may not match. The suggestions are the following:
    276 
    277     - If you want to use the GMP version under /usr, then you should
    278       uninstall all the other GMP versions (header and library files)
    279       that may be seen in the search paths, in particular those under
    280       /usr/local.
    281 
    282     - If you want to use the GMP version under /usr/local, then you
    283       should uninstall all the other GMP versions (header and library
    284       files) that may be seen in the search paths, but *NOT* the one
    285       under /usr (the version under /usr is provided by the OS vendor,
    286       and changing/removing anything related to it may break your
    287       system, and /usr should have a lower precedence than /usr/local
    288       anyway).
    289 
    290   To find where GMP versions have been installed:
    291 
    292     $ locate libgmp  (if you have a locate database)
    293 
    294   and if the compiler is GCC:
    295 
    296     $ gcc -print-file-name=libgmp.so     (under most systems)
    297     $ gcc -print-file-name=libgmp.dylib  (under Mac OS X)
    298 
    299   and if this does not work, you may try:
    300 
    301     $ gcc -print-search-dirs
    302 
    303 * An official GCC version was used under Debian GNU/Linux. Problems
    304   may come from the fact that Debian chose a different convention
    305   for library search paths concerning 32-bit and 64-bit libraries.
    306   A possible problem can be, for instance:
    307 
    308   [Debian's GCC, correct library path]
    309   $ gcc -print-file-name=libgmp.so
    310   /home/vlefevre/gmp/athlon64/lib/../lib/libgmp.so
    311 
    312   [Official GCC, incorrect library path]
    313   $ gcc-4.3.1 -print-file-name=libgmp.so
    314   /usr/lib/../lib64/libgmp.so
    315 
    316   The solution: use a GCC provided by Debian or add symbolic links
    317   such as lib64 -> lib (on 64-bit machines) for your library paths.
    318 
    319 * The problem may also be temporary and only due to the fact that
    320   libtool could not be used at this time. This is unlikely, though.
    321 
    322 
    323 In case of problem
    324 ==================
    325 
    326 First, look for any warning message in the configure output.
    327 
    328 Several documents may help you to solve the problem:
    329   * this INSTALL file, in particular information given below;
    330   * the FAQ (either the FAQ.html file distributed with MPFR, or the
    331     on-line version <http://www.mpfr.org/faq.html>, which may be more
    332     up-to-date);
    333   * the MPFR web page for this version <http://www.mpfr.org/mpfr-3.1.2/>,
    334     which lists bugs found in this version and provides some patches.
    335 
    336 If the "configure" fails, please check that the C compiler and its
    337 options are the same as those for the GMP build (specially the ABI).
    338 You can see the latter with the following command:
    339 
    340   grep "^CC\|^CFLAGS" GMPBUILD/Makefile
    341 
    342 if the GMP build directory is available. Then type:
    343 
    344   ./configure <configure options> CC=<C compiler> CFLAGS="<compiler options>"
    345 
    346 (quotes are needed when there are spaces or other special characters
    347 in the CC/CFLAGS value) and continue the install. On some platforms,
    348 you should provide further options to match those used by GMP, or set
    349 some environment variables. For instance, see the "Notes on AIX/PowerPC"
    350 section below.
    351 
    352 Warning! Do NOT use optimization options that can change the semantics
    353 of math operations, such as GCC's -ffast-math or Sun CC's -fast.
    354 Otherwise conversions from/to double's may be incorrect on infinities,
    355 NaN's and signed zeros. Since native FP arithmetic is used in a few
    356 places only, such options would not make MPFR faster anyway.
    357 
    358 If some "make check" tests fail, you can try the --disable-thread-safe
    359 configure option (see the configure options above): it has been reported
    360 that some platforms have buggy TLS support. Before trying this option,
    361 you may want to check in the configure output whether MPFR was built
    362 with TLS support; if yes, you will have a line:
    363   checking for TLS support... yes
    364 Alternatively "grep MPFR_USE_THREAD_SAFE config.log" will show that
    365 MPFR_USE_THREAD_SAFE is defined to 1. If it is "no" (or the variable
    366 is not defined), the --disable-thread-safe option would be useless.
    367 
    368 Some tests failure may be due to other compiler bugs, in particular
    369 in optimization code. You can try to build MPFR without compiler
    370 optimizations by giving -O0 (letter O, digit 0) in CFLAGS. If the
    371 MPFR tests no longer fail, this was probably due to a compiler bug,
    372 though we cannot exclude a bug in MPFR. You may want to contact us
    373 (see below), possibly after looking at:
    374   http://www.loria.fr/~zimmerma/software/compilerbugs.html
    375 
    376 On some platforms, try with "gmake" (GNU make) instead of "make".
    377 Problems have been reported with the Tru64 make.
    378 
    379 If the configure script reports that gmp.h version and libgmp version
    380 are different, or if the build was OK, but the tests failed to link
    381 with GMP or gave an error like
    382 
    383   undefined reference to `__gmp_get_memory_functions'
    384 
    385 meaning that the GMP library was not found or a wrong GMP library was
    386 selected by the linker, then your library search paths are probably
    387 not correctly set (some paths are missing or they are specified in an
    388 incorrect order).
    389 
    390 Such problems commonly occur under some GNU/Linux machines, where the
    391 default header and library search paths may be inconsistent: GCC is
    392 configured to search /usr/local/include and /usr/local/lib by default,
    393 while the dynamic linker ignores /usr/local/lib. If you have a GMP
    394 version installed in /usr (provided by the OS vendor) and a new one
    395 installed in /usr/local, then the header of the new GMP version and
    396 the library of the old GMP version will be used! The best solution
    397 is to make sure that the dynamic linker configuration is consistent
    398 with GCC's behavior, for instance by having /usr/local/lib in
    399 /etc/ld.so.conf or in some file from /etc/ld.so.conf.d (as Debian
    400 did: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=395177). See
    401 also http://gcc.gnu.org/ml/gcc-help/2010-01/msg00171.html for more
    402 information. Alternatively you can use:
    403   * environment variables. This may sometimes be necessary. If DIR
    404     is the installation directory of GMP, add DIR/include to your
    405     CPATH or C_INCLUDE_PATH (for compilers other than GCC, please
    406     check the manual of your compiler), and add DIR/lib to your
    407     LIBRARY_PATH and LD_LIBRARY_PATH (and/or LD_RUN_PATH);
    408   * --with-gmp* configure options (described above), e.g.
    409     --with-gmp=/opt/local (to use /opt/local/include for headers and
    410     /opt/local/lib for libraries), but other software that uses GMP
    411     and/or MPFR will need correct paths too, and environment variables
    412     allow one to set such search paths in a global way.
    413     Note about "--with-gmp=/usr/local". This option may appear to
    414     solve the above inconsistency problem, but does not work as you
    415     expect. Indeed it affects the library search path, in particular,
    416     the one used by the dynamic linker (thus adding the missing
    417     /usr/local/lib directory as wanted), but since /usr/local/include
    418     is a "standard system include directory" for GCC, the include
    419     search patch is not changed; this is often not a problem in this
    420     particular case because usually, /usr/local/include is already
    421     last in the include search patch, but this may fail under some
    422     occasions and may trigger obscure errors.
    423 
    424 For instance, under Unix, where paths are separated by a colon:
    425 
    426   * With POSIX sh-compatible shells (e.g. sh, ksh, bash, zsh):
    427     export C_INCLUDE_PATH="/usr/local/include:/other/path/include"
    428     export LIBRARY_PATH="/usr/local/lib:/other/path/lib"
    429     export LD_LIBRARY_PATH="$LIBRARY_PATH"
    430 
    431   * With csh or tcsh:
    432     setenv C_INCLUDE_PATH "/usr/local/include:/other/path/include"
    433     setenv LIBRARY_PATH "/usr/local/lib:/other/path/lib"
    434     setenv LD_LIBRARY_PATH "$LIBRARY_PATH"
    435 
    436 If you can't solve your problem, you should contact us via the MPFR
    437 mailing-list <mpfr (a] inria.fr>, indicating the machine and operating system
    438 used (uname -a), the compiler and version used (gcc -v if you use gcc),
    439 the configure options used if any (including variables such as CC and
    440 CFLAGS), the version of GMP and MPFR used, and a description of the
    441 problem encountered. Please send us also the log of the "configure"
    442 (config.log).
    443 
    444 Note that even if you can build MPFR with a C++ compiler, you can't run
    445 the test suite: C and C++ are not the same language! You should use a C
    446 compiler instead.
    447 
    448 
    449 Notes about ABI
    450 ===============
    451 
    452 On 64-bit computers, it may happen that the default ABI (Application Binary
    453 Interface) chosen by MPFR does not correspond to the default one chosen by
    454 the compiler.
    455 
    456 In particular, this kind of message may indicate the problem:
    457 /usr/bin/ld: skipping incompatible mpfr/src/.libs/libmpfr.a when searching for -lmpfr
    458 
    459 In fact, since MPFR relies on GMP, it uses the same ABI as GMP.
    460 To be sure that your program compiles and links correctly, use the same
    461 compiler flags as MPFR does (look for CFLAGS in config.log).
    462 
    463 You might also recompile GMP with a different ABI, with for example
    464 ./configure ABI=32.
    465 
    466 
    467 Notes on Mac OS X
    468 =================
    469 
    470 If you get an error of the form
    471 
    472   ld: pointer in read-only segment not allowed in slidable image...
    473 
    474 this can mean that the link is done against a static (GMP) library.
    475 In such a case, you should configure MPFR with --disable-shared to
    476 disable the build of the shared library.
    477 
    478 
    479 Notes on FreeBSD 4.3
    480 ====================
    481 
    482 FreeBSD 4.3 is provided with an incorrect <float.h> header file, and
    483 MPFR tests related to long double's may fail. If you cannot upgrade
    484 the system, you can still use MPFR with FreeBSD 4.3, but you should
    485 not use conversions with the long double type.
    486 
    487 
    488 Notes on AIX/PowerPC
    489 ====================
    490 
    491 The following has been tested on AIX 5.3 (powerpc-ibm-aix5.3.0.0) with
    492 gcc 3.3.2 and GMP 4.2.1.
    493 
    494 If GMP was built with the 64-bit ABI, before building and testing MPFR,
    495 you should set the OBJECT_MODE environment variable to 64, e.g., with:
    496 
    497   export OBJECT_MODE=64
    498 
    499 (in a sh-compatible shell). But you should also provide a correct CFLAGS
    500 value to the "configure" script: using --with-gmp-build is not sufficient
    501 due to the early compiler tests, as gcc will not compile any program if
    502 OBJECT_MODE is 64 and the -maix64 option is not provided.
    503 
    504 
    505 MPFR for use with 32-bit Windows Applications (win32)
    506 =====================================================
    507 
    508 There are several ways of building MPFR on Windows, the most appropriate
    509 approach depending on how you intend to use the resulting libraries.
    510 
    511 a. Using MinGW
    512 ==============
    513 
    514 1 - We advise to use MinGW (http://www.mingw.org/), which is simpler and
    515     less demanding than Cygwin. Contrary to Cygwin, it also provides native
    516     Windows code.
    517 
    518 2 - If you just want to make a binary with gcc, there is nothing to do:
    519     GMP, MPFR and the program compile exactly as under Linux.
    520     But if you want to generate a library for MinGW from a Cygwin
    521     environment, you may need the -mno-cygwin gcc option (otherwise
    522     a typical error is _P_WAIT being undeclared).
    523 
    524 3 - If you want to make libraries work under another Windows compiler
    525     like Visual C / C++, since the unix-like *.a library files are compatible
    526     with Windows *.lib files, you can simply rename all *.a libraries to *.lib.
    527 
    528     With gmp-4.1.3, the only remaining problem seems to be the "alloca" calls
    529     in GMP. Configuring GMP and MPFR with --enable-alloca=malloc-reentrant
    530     should work (if you build MPFR with GMP internal files).
    531 
    532     Or you could add the library
    533      "$MINGWIN$/lib/gcc-lib/mingw32/$VERSION$/libgcc.a"
    534     to your project: it contains all the extra-functions needed by a program
    535     compiled by gcc (division of 64-bit integer, bcopy, alloca...).
    536     Of course, include it if and only if your compiler is not gcc.
    537 
    538 4 - On Windows32 / MinGW, if all the tests fail, try to run the test suite
    539     with "make check EXEEXT=".
    540 
    541 5 - To avoid using the Microsoft runtime (which might not be conform to ISO C),
    542     you can use the MinGW runtime package (which is an integral part of MinGW).
    543     For example, with MinGW versions 3.15 and later you can get an
    544     ISO-compliant printf() if you compile your application with either
    545     '-ansi', '-posix' or '-D__USE_MINGW_ANSI_STDIO'. For example, you can
    546     compile and test MPFR with CC="gcc -D__USE_MINGW_ANSI_STDIO".
    547 
    548     For example under Win32, the following problem has been experienced with
    549     MPFR 2.4.0 RC1 and the MSVC runtime (msvcrt.dll):
    550 
    551        Error in mpfr_vsprintf (s, "%.*Zi, %R*e, %Lf%n", ...);
    552        expected: "00000010610209857723, -1.2345678875e+07, 0.032258"
    553        got:      "00000010610209857723, -1.2345678875e+07, -0.000000"
    554        FAIL: tsprintf.exe
    555 
    556     This error is due to the MSVC runtime not supporting the L length modifier
    557     for formatted output (e.g. printf with %Lf). You can check this with the
    558     following program:
    559 
    560        #include <stdio.h>
    561        int main (void)
    562        {
    563          long double d = 1. / 31.;
    564          printf ("%Lf\n", d);
    565          return 0;
    566        }
    567 
    568     The expected output is 0.032258.
    569 
    570     Note: The L modifier has been standard for a long time (it was added
    571     in ISO C89).
    572 
    573     Note 2: this now works correctly with Visual C++ 2008 and 2010
    574     (tested on Microsoft (R) 32-bit C/C++ Optimizing Compiler Version
    575      15.00.21022.08 for 80x86, Microsoft (R) C/C++ Optimizing Compiler
    576      Version 15.00.21022.08 for x64, Microsoft (R) 32-bit C/C++ Optimizing
    577      Compiler Version 16.00.30319.01 for 80x86, Microsoft (R) C/C++ Optimizing
    578      Compiler Version 16.00.30319.01 for x64).
    579 
    580 b. Using Cygwin
    581 ===============
    582 
    583 This build should be similar to that for MinGW except that the resulting
    584 library depends on the Cygwin DLL and cannot therefore be used with
    585 Visual Studio as with MinGW. Indeed, the binaries compiled with Cygwin
    586 require a dynamic library (cygwin.dll) to work; there is a Cygwin option
    587 -mno-cygwin to build native code, but it may require some non-portable tricks.
    588 
    589 In case of failure, you may need to pass LDFLAGS='-shared-libgcc' at the
    590 end of the configure line due to a bug in GCC. Otherwise, if threading
    591 support is not needed, you can configure MPFR with --disable-thread-safe.
    592 
    593 c. Using Visual C++ 2008/2010
    594 =============================
    595 
    596 Win32 versions of the MPFR library can be built using Microsoft Visual
    597 C++ 2008 or 2010 using the build projects available here:
    598 
    599 http://gladman.plushost.co.uk/oldsite/computing/gmp4win.php
    600 
    601 These build projects contain both win32 and x64 builds but the latter
    602 will give errors if your version of Visual C++ lacks the 64-bit
    603 compiler and tools.   The 32-bit build projects should however work
    604 on Visual C++ 2008, Visual C++ Express 2008 (SP1), Visual C++ 2010
    605 and Visual C++ Express 2010.
    606 
    607 MPFR for use with 64-bit Windows Applications (x64)
    608 ===================================================
    609 
    610 There are two ways of building MPFR for use with 64-bit Windows
    611 applications.
    612 
    613 a. Using MinGW64
    614 ================
    615 
    616 The MinGW64 version of the GCC compiler is now available here:
    617 
    618 http://sourceforge.net/projects/mingw-w64/
    619 
    620 It can build both GMP and MPFR for 64-bit Windows applications.
    621 
    622 b. Using Visual C++ 2008/2010
    623 =============================
    624 
    625 x64 versions of the MPFR library can be built using Microsoft Visual
    626 C++ 2008 or 2010 using the build projects available here:
    627 
    628 http://gladman.plushost.co.uk/oldsite/computing/gmp4win.php
    629 
    630 These build projects contain both win32 and x64 builds but the latter
    631 can only be built if your version of Visual C++ contains the 64-bit
    632 compiler and tools.  On Visual C++ 2008, the 64-bit tools are an
    633 option during installation so if you don't have them you will need
    634 to start the Visual Studio installer and add them to your IDE
    635 configuration.  On Visual C++ 2010 they are installed by default.
    636 
    637 As delivered, Visual C++ Express 2008 SP1 cannot build x64 projects
    638 but the Windows SDK can be added to it to allow this. The IDE then
    639 needs to be configured as described here:
    640 
    641 http://msdn.microsoft.com/en-us/library/9yb4317s(VS.80).aspx
    642 
    643 to allow x64 builds.
    644 
    645 Visual C++ Express 2010 requires the Windows 7 SDK to be installed
    646 in order to build x64 projects. This SDK is available here:
    647 
    648 http://tinyurl.com/25zz8r6
    649 
    650 In this case, once this SDK has been installed, Visual C++ Express 2010
    651 will build x64 projects without further changes.
    652