Copyright 1999-2023 Free Software Foundation, Inc. Contributed by the AriC and Caramba projects, INRIA. This file is part of the GNU MPFR Library. The GNU MPFR Library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version. The GNU MPFR Library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with the GNU MPFR Library; see the file COPYING.LESSER. If not, see https://www.gnu.org/licenses/ or write to the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. Installing GNU MPFR =================== Note: In case of problem, please read this INSTALL file carefully before reporting a bug, in particular Section "In case of problem" below. Some problems are due to bad configuration on the user side (not specific to MPFR). 0. You first need to install GMP. See . MPFR requires GMP version 5.0.0 or later. You need a C compiler, preferably GCC, but any reasonable compiler should work (C++ compilers should work too, under the condition that they do not break type punning via union). And you need the standard Unix "make" command, plus some other standard Unix utility commands. 1. Extract the files from the archive. 2. It is strongly advised to apply the latest patches if this has not been done yet and if patches are available. You can check on the release page: https://www.mpfr.org/mpfr-4.2.1/ which may have additional information. The patches can be applied with commands like: wget --no-config https://www.mpfr.org/mpfr-4.2.1/allpatches patch -N -Z -p1 < allpatches or curl https://www.mpfr.org/mpfr-4.2.1/allpatches | patch -N -Z -p1 (Those instructions are for the GNU patch command, for example /usr/bin/gpatch on Solaris.) 3. In the MPFR directory, to detect your system, type: ./configure possibly with options (see below, in particular if this step or one of the following fails). You should also check whether WARNING lines have been output (such a problem may cause a failure in one of the following steps). Note: paths provided in configure options must always be absolute (relative paths are not supported). 4. To build the library, type: make [optional] if you want to tune MPFR for your specific architecture, see the section "Tuning MPFR" below. Note that for most common architectures, MPFR includes some default tuning parameters which should be near from optimal. 5. To check the built library (runs the test files), type: make check Note: If any test fails, information about this failure can be found in the tests/test-suite.log file; you should provide this file in your bug reports (in addition to other useful information, as mentioned later). If you want the contents of this file to be automatically output in case of failure, you can set the VERBOSE environment variable to 1 before running "make check", for instance by typing: VERBOSE=1 make check 6. [Optional / experimental] Binary distributions may also want to run: make check-gmp-symbols This will check that MPFR does not use GMP internal symbols, which could yield failures in case of GMP upgrade without a MPFR rebuild. But note that this is a heuristic and might give false positives or false negatives. Please report any problem to the MPFR developers. End users may also be interested in this check, unless they have allowed GMP internals with configure options (see below). 7. To install it (default "/usr/local" | see "--prefix" option), type: make install If you installed MPFR (header and library) in directories that are not searched by default by the compiler and/or linking tools, then, like with other libraries, you may need to set up some environment variables such as C_INCLUDE_PATH (to find the header mpfr.h), LIBRARY_PATH (to find the library), and if the shared library has been installed, LD_LIBRARY_PATH (before execution) or LD_RUN_PATH (before linking); this list is not exhaustive and some environment variables may be specific to your system. "make install" gives some instructions; please read them. You can also find more information in the manuals of your compiler and linker. The MPFR FAQ may also give some information. Remember that if you have several MPFR (or GMP) versions installed (e.g., one with the system, and one, newer, by you), you will not necessarily get a compilation/linking error if a wrong library is used (e.g., because LD_LIBRARY_PATH has not been set correctly). But unexpected results may occur. Under Mac OS X, if the shared library was not installed and you use Apple's linker (this is the default), you will also need to provide the -search_paths_first linker flag ("-Wl,-search_paths_first" when you link via gcc) to make sure that the right library is selected, as by default, Apple's linker selects a shared library preferably, even when it is farther in the library paths. We recall that if a wrong library is selected due to this behavior, unexpected results may occur. Building the documentation ========================== To build the documentation in various formats, you may first need to install recent versions of some utilities such as texinfo. * Type "make info" to produce the documentation in the info format. * Type "make pdf" to produce the documentation in the PDF format. * Type "make dvi" to produce the documentation in the DVI format. * Type "make ps" to produce the documentation in the PostScript format. * Type "make html" to produce the documentation in the HTML format (in several pages); if you want only one output HTML file, then type "makeinfo --html --no-split mpfr.texi" from the doc directory instead. Building MPFR with internal GMP header files ============================================ MPFR built with internal GMP header files is a bit faster, so you may want to build it with them. Just do this in step 1: ./configure --with-gmp-build=GMPBUILD where GMPBUILD is the GMP build directory. The needed header files are: gmp-impl.h, longlong.h and all the necessary headers to use them, which may be located either in the GMP source directory or in the GMP build directory, in case they are different (MPFR takes care of that, as of MPFR 3.1.0). Warning: the library obtained in this way may use some internal GMP symbols, and thus dynamically linking your software with a different version of GMP might fail, even though it is declared as compatible by Libtool's versioning system. Tuning MPFR =========== [For the current GMP version (6.1.0), a Unix-like OS is required.] For this, you need to build MPFR with a GMP build directory (see above). In the GMP build directory, you also need to go into the "tune" subdirectory and type "make speed". This will build the GMP speed library, which is used by the MPFR tuning mechanism. Then go back to the MPFR build directory, go into the "tune" subdirectory and type "make tune". This will build an optimized file "mparam.h" for your specific architecture. ./configure options =================== --prefix=DIR installs MPFR headers and library in DIR/include and DIR/lib respectively (the default is "/usr/local"). --with-gmp-include=DIR assumes that DIR contains gmp.h --with-gmp-lib=DIR assumes that DIR contains the GMP library --with-gmp=DIR assumes that DIR is where you have installed GMP. same as --with-gmp-lib=DIR/lib and --with-gmp-include=DIR/include (use either --with-gmp alone or one or both of --with-gmp-lib/--with-gmp-include) Warning! Do not use these options if you have CPPFLAGS and/or LDFLAGS containing a -I or -L option with a directory that contains a GMP header or library file, as these options just add -I and -L options to CPPFLAGS and LDFLAGS *after* the ones that are currently declared, so that DIR will have a lower precedence. Also, this may not work if DIR is a system directory (typically /usr or /usr/local); see below. --with-gmp-build=DIR assumes that DIR contains the GMP build directory, and enables the use of GMP internals (see above). Warning! This option and the group of options --with-gmp are mutually exclusive. --enable-assert build MPFR with assertions. --enable-thread-safe build MPFR as thread safe, using compiler-level Thread-Local Storage (TLS). Note: TLS support is roughly tested by configure. If configure detects that TLS does not work (because of the compiler, linker or system libraries), it will output an error message, telling you to build MPFR without thread safe. For instance, though Mac OS X uses GCC, it may not currently support GCC's __thread storage class. --disable-thread-safe build MPFR without TLS. By default, TLS support is detected automatically, and MPFR is built as thread safe if supported. However, this detection is only a heuristic: TLS can be detected as supported while its support is incomplete or buggy (MPFR tests may fail). In such a case, this option is useful. --enable-decimal-float build conversion functions from/to decimal floats. Note that detection by the configure script is limited in case of cross-compilation. Accepted arguments: yes Decimal support is requested and the configure script fails if it detects that decimals do not work. The encoding (BID or DPD) will automatically be detected at configure time or at compile time if possible (if not, generic code will be used). no Decimal support is explicitly disabled. auto Decimal support is enabled if the configure script detects that it works. This is the default when --{enable,disable}-decimal-float is not given. bid Decimal support is requested and the encoding is assumed to be BID (some check may be done). dpd Decimal support is requested and the encoding is assumed to be DPD (some check may be done). generic Decimal support is requested and the generic code is used (mainly for developers). --enable-gmp-internals allows the MPFR build to use GMP's undocumented functions (not from the public API). Note that library versioning is not guaranteed to work if this option is used. Thus it must not be used in binary distributions. --with-sysroot=DIR Search for dependent libraries within DIR (which may be useful in cross-compilation). If you use this option, you need to have Libtool 2.4+ on the target system. See Libtool 2.4+'s NEWS file. Note: By default, the configure script tries to set CC / CFLAGS to GMP's ones from gmp.h (__GMP_CC / __GMP_CFLAGS) in order to ensure that MPFR is built with the same ABI as GMP. The reason is that when GMP is built, it may set CC / CFLAGS to select an ABI that is not the default one in order to have a better performance. The -pedantic option in GMP's CFLAGS, when present (which is the case by default), is removed, because the MPFR build system uses some C extensions (when this script detects that they are supported) and -pedantic yields too many useless warnings. However, this setting from GMP is not guaranteed to work as the configure script does some compiler tests earlier, and a conflict may arise. Also, the values obtained from GMP may be incorrect for the MPFR build if GMP has been built on a different machine; in such a case, the user may need to specify CC / CFLAGS, as explained below. Moreover, even without --with-gmp-build and --enable-gmp-internals, MPFR might use some GMP internals by mistake. This would be a bug, which should be reported to the MPFR developers. Run "./configure --help" to see the other options (default options from Autoconf and Automake). If 'gmp.h' and 'libgmp' do not match ==================================== Under some circumstances, the configure script may output a message saying: 'gmp.h' and 'libgmp' seem to have different versions or we cannot run a program linked with GMP (if you cannot see the version numbers above). [...] Even though the configure script does not fail in such a case, this message most often indicates a real error, which needs to be avoided. Possible causes are: * The wanted GMP library does not have the same ABI as the one chosen to build MPFR. The consequences may be: - A different GMP library (with the correct ABI) has been found, but does not have the same version as 'gmp.h'. - No other GMP libraries have been found (in this case, no version numbers should be printed above the warning message). This is incorrect and one of the following steps (make, make check) will probably fail. GMP (actually gmp.h) now provides CC and CFLAGS information to select the correct ABI, so that this problem should no longer occur; but if GMP was provided by a binary package, such information may not be valid. See the checking for CC and CFLAGS in gmp.h... line in the configure output (about the 11th line) and the following few ones for more information. You may need to reinstall GMP or to provide your own CC and/or CFLAGS. See also the remaining of this INSTALL file. * A configure option like --with-gmp or --with-gmp-include was used with a system include directory, e.g. one of the following: --with-gmp=/usr --with-gmp=/usr/local --with-gmp-include=/usr/include --with-gmp-include=/usr/local/include GCC (and possibly other compilers) will ignore such a directive for include directories (but this rule is not applied for the library itself!). This means that the library search paths will be reordered as declared, but the specified include directory will still be near the end of the include search paths (thus with a low precedence). This is not a problem if only one GMP version is installed, but otherwise, a wrong gmp.h may be chosen, so that the versions of gmp.h and libgmp may not match. The suggestions are the following: - If you want to use the GMP version under /usr, then you should uninstall all the other GMP versions (header and library files) that may be seen in the search paths, in particular those under /usr/local. - If you want to use the GMP version under /usr/local, then you should uninstall all the other GMP versions (header and library files) that may be seen in the search paths, but *NOT* the one under /usr (the version under /usr is provided by the OS vendor, and changing/removing anything related to it may break your system, and /usr should have a lower precedence than /usr/local anyway). To find where GMP versions have been installed: $ locate libgmp (if you have a locate database) and if the compiler is GCC: $ gcc -print-file-name=libgmp.so (under most systems) $ gcc -print-file-name=libgmp.dylib (under Mac OS X) and if this does not work, you may try: $ gcc -print-search-dirs * An official GCC version was used under Debian GNU/Linux. Problems may come from the fact that Debian chose a different convention for library search paths concerning 32-bit and 64-bit libraries. A possible problem can be, for instance: [Debian's GCC, correct library path] $ gcc -print-file-name=libgmp.so /home/vlefevre/gmp/athlon64/lib/../lib/libgmp.so [Official GCC, incorrect library path] $ gcc-4.3.1 -print-file-name=libgmp.so /usr/lib/../lib64/libgmp.so The solution: use a GCC provided by Debian or add symbolic links such as lib64 -> lib (on 64-bit machines) for your library paths. * The problem may also be temporary and only due to the fact that libtool could not be used at this time. This is unlikely, though. In case of problem ================== First, look for any warning message in the configure output. Several documents may help you to solve the problem: * this INSTALL file, in particular information given below; * the FAQ (either the FAQ.html file distributed with MPFR, or the on-line version , which may be more up-to-date); * the MPFR web page for this version , which lists bugs found in this version and provides some patches. If the "configure" fails, please check that the C compiler and its options are the same as those for the GMP build (specially the ABI). You can see the latter with the following command: grep "^CC\|^CFLAGS" GMPBUILD/Makefile if the GMP build directory is available. Then type: ./configure CC= CFLAGS="" (quotes are needed when there are spaces or other special characters in the CC/CFLAGS value) and continue the install. On some platforms, you should provide further options to match those used by GMP, or set some environment variables. For instance, see the "Notes on AIX/PowerPC" section below. Warning! Do NOT use optimization options that can change the semantics of math operations, such as GCC's -ffast-math or Sun CC's -fast. Otherwise conversions from/to double's may be incorrect on infinities, NaN's and signed zeros. Since native FP arithmetic is used in a few places only, such options would not make MPFR faster anyway. If some "make check" tests fail, you can try the --disable-thread-safe configure option (see the configure options above): it has been reported that some platforms have buggy TLS support. Before trying this option, you may want to check in the configure output whether MPFR was built with TLS support; if yes, you will have a line: checking for TLS support... yes Alternatively "grep MPFR_USE_THREAD_SAFE config.log" will show that MPFR_USE_THREAD_SAFE is defined to 1. If it is "no" (or the variable is not defined), the --disable-thread-safe option would be useless. Some tests failure may be due to other compiler bugs, in particular in optimization code. You can try to build MPFR without compiler optimizations by giving -O0 (letter O, digit 0) in CFLAGS. If the MPFR tests no longer fail, this was probably due to a compiler bug, though we cannot exclude a bug in MPFR. You may want to contact us (see below), possibly after looking at: https://members.loria.fr/PZimmermann/software/compilerbugs.html On some platforms, try with "gmake" (GNU make) instead of "make". Problems have been reported with the Tru64 make. If the configure script reports that gmp.h version and libgmp version are different, or if the build was OK, but the tests failed to link with GMP or gave an error like undefined reference to `__gmp_get_memory_functions' meaning that the GMP library was not found or a wrong GMP library was selected by the linker, then your library search paths are probably not correctly set (some paths are missing or they are specified in an incorrect order). Such problems commonly occur under some GNU/Linux machines, where the default header and library search paths may be inconsistent: GCC is configured to search /usr/local/include and /usr/local/lib by default, while the dynamic linker ignores /usr/local/lib. If you have a GMP version installed in /usr (provided by the OS vendor) and a new one installed in /usr/local, then the header of the new GMP version and the library of the old GMP version will be used! The best solution is to make sure that the dynamic linker configuration is consistent with GCC's behavior, for instance by having /usr/local/lib in /etc/ld.so.conf or in some file from /etc/ld.so.conf.d (as Debian did: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=395177). See also https://gcc.gnu.org/legacy-ml/gcc-help/2010-01/msg00171.html for more information. Alternatively you can use: * environment variables. This may sometimes be necessary. If DIR is the installation directory of GMP, add DIR/include to your CPATH or C_INCLUDE_PATH (for compilers other than GCC, please check the manual of your compiler), and add DIR/lib to your LIBRARY_PATH and LD_LIBRARY_PATH (and/or LD_RUN_PATH); * --with-gmp* configure options (described above), e.g. --with-gmp=/opt/local (to use /opt/local/include for headers and /opt/local/lib for libraries), but other software that uses GMP and/or MPFR will need correct paths too, and environment variables allow one to set such search paths in a global way. Note about "--with-gmp=/usr/local". This option may appear to solve the above inconsistency problem, but does not work as you expect. Indeed it affects the library search path, in particular, the one used by the dynamic linker (thus adding the missing /usr/local/lib directory as wanted), but since /usr/local/include is a "standard system include directory" for GCC, the include search patch is not changed; this is often not a problem in this particular case because usually, /usr/local/include is already last in the include search patch, but this may fail under some occasions and may trigger obscure errors. For instance, under Unix, where paths are separated by a colon: * With POSIX sh-compatible shells (e.g. sh, ksh, bash, zsh): export C_INCLUDE_PATH="/usr/local/include:/other/path/include" export LIBRARY_PATH="/usr/local/lib:/other/path/lib" export LD_LIBRARY_PATH="$LIBRARY_PATH" * With csh or tcsh: setenv C_INCLUDE_PATH "/usr/local/include:/other/path/include" setenv LIBRARY_PATH "/usr/local/lib:/other/path/lib" setenv LD_LIBRARY_PATH "$LIBRARY_PATH" If almost all the tests fail and the messages in the test-suite.log file (or in the output, when running individual tests from the command line) start with a line of the form: Incorrect MPFR version! (xxx header vs yyy library) then this means that an installed MPFR version is tested instead of the one that has just been built. This is probably not a bug in MPFR, but a problem caused by the user or system configuration (particular options, environment variables, etc.) or a bug in the toolchain. In particular, if LD_LIBRARY_PATH overrides the run path (set up by libtool) and an installed ABI-compatible version of MPFR is in a directory listed in the LD_LIBRARY_PATH search path, then this will break. An example with GNU ld: https://sourceware.org/bugzilla/show_bug.cgi?id=21476 If you can't solve your problem, you should contact us via the MPFR mailing-list , indicating the machine and operating system used (uname -a), the compiler and version used (gcc -v if you use gcc), the configure options used if any (including variables such as CC and CFLAGS), the version of GMP and MPFR used, and a description of the problem encountered, in particular the tests/test-suite.log file if "make check" failed. Please send us also the log of the "configure" (config.log). Notes about ABI =============== On 64-bit computers, it may happen that the default ABI (Application Binary Interface) chosen by MPFR does not correspond to the default one chosen by the compiler. In particular, this kind of message may indicate the problem: /usr/bin/ld: skipping incompatible mpfr/src/.libs/libmpfr.a when searching for -lmpfr In fact, since MPFR relies on GMP, it uses the same ABI as GMP. To be sure that your program compiles and links correctly, use the same compiler flags as MPFR does (look for CFLAGS in config.log). You might also recompile GMP with a different ABI, with for example ./configure ABI=32. Notes on Mac OS X ================= If you get an error of the form ld: pointer in read-only segment not allowed in slidable image... this can mean that the link is done against a static (GMP) library. In such a case, you should configure MPFR with --disable-shared to disable the build of the shared library. Notes on FreeBSD 4.3 ==================== FreeBSD 4.3 is provided with an incorrect header file, and MPFR tests related to long double's may fail. If you cannot upgrade the system, you can still use MPFR with FreeBSD 4.3, but you should not use conversions with the long double type. Notes on AIX/PowerPC ==================== The following has been tested on AIX 7.1.3 (gcc111.fsffrance.org) with gcc 4.8.1 and GMP 6.1.0. If GMP was built with the 64-bit ABI, before building and testing MPFR, you should set the OBJECT_MODE environment variable to 64, e.g., with: export OBJECT_MODE=64 (in a sh-compatible shell). Alternatively add the following to the configure line: AR="ar -X64" NM="nm -B -X64". Notes on Solaris ================ Do not put a -R option in the LD_OPTIONS environment variable, at least if the directory can contain an MPFR library. Otherwise this MPFR library may be chosen for the tests (make check) instead of the one that has just been built, in which case, either you will get errors due to unmatched versions or this problem may remain undetected. The reason is that this option will appear before the -R options added by libtool, such as the one to the src/.libs directory containing the MPFR library that has just been built, and will have the precedence. MPFR for use with Windows Applications ====================================== There are several ways of building MPFR on Windows, the most appropriate approach depending on how you intend to use the resulting libraries. a. Using MinGW ============== 1 - We advise to use Mingw-w64 (https://www.mingw-w64.org/), which is simpler and less demanding than Cygwin. Contrary to Cygwin, it also provides native Windows code. If you also use MSYS, you should use "make" for MSYS instead of the "make" utility from Mingw-w64 or from GCC, which causes the following error: libtool: warning: libobj name 'extract.Tpo -c -o extract.lo extract.lo' may not contain shell special characters. rm: unknown option -- c References about this issue and solution: https://sourceforge.net/p/msys2/tickets/223/ https://sympa.inria.fr/sympa/arc/mpfr/2016-07/msg00009.html 2 - If you just want to make a binary with gcc, there is nothing to do: GMP, MPFR and the program compile exactly as under Linux. (It is recommended to pass --build=xxx-yyy-mingw64 to the GMP configure command, or --build=xxx with xxx containing mingw.) 3 - To avoid using the Microsoft runtime (which might not be conform to ISO C), you can use the MinGW runtime package (which is an integral part of MinGW). With MinGW version v8.0.0 and later, the formatted output functions (printf, etc.) are ISO/POSIX-conforming by default; however, this is no longer true if -std=c89 is used at build time. Conversely, with earlier MinGW versions, it is possible to get conforming functions with either '-ansi', '-posix' or '-D__USE_MINGW_ANSI_STDIO'. Note that if there is a conformity mismatch between the options used for the GMP build (from which the MPFR build gets the output) and those used for the MPFR tests, the tsprintf test may fail with one of the errors below. Be careful that a non-conforming output may yield a buffer overflow. The following applies to old MinGW versions, and may be discouraged with recent MinGW versions. In order to have the MPFR formatted output functions based on an ISO-conforming printf(), you need to compile GMP (not MPFR) with CC="gcc -D__USE_MINGW_ANSI_STDIO" (since the standard printf modifiers %e, %Ld and %td are passed to GMP). To avoid failures of some of the printf-related tests, MPFR needs to be compiled with the same __USE_MINGW_ANSI_STDIO as with GMP, i.e. this macro should be defined for both or undefined for both; this should be the case by default, unless CC or CFLAGS has been redefined. For instance, if __USE_MINGW_ANSI_STDIO is defined in GMP but not in MPFR, the following error may occur: Error in mpfr_vsprintf (s, "%e", ...); expected: "-1.250000e+000" got: "-1.250000e+00" FAIL tsprintf.exe (exit status: 1) and in the opposite case: Error in mpfr_vsprintf (s, "%e", ...); expected: "-1.250000e+00" got: "-1.250000e+000" FAIL tsprintf.exe (exit status: 1) Note with old GMP versions: Other issues could arise due to the fact that the C functions vsnprintf and vsprintf both used internally in old GMP versions do not produce the same output: https://sympa.inria.fr/sympa/arc/mpfr/2016-03/msg00045.html https://sympa.inria.fr/sympa/arc/mpfr/2016-03/msg00051.html https://sympa.inria.fr/sympa/arc/mpfr/2016-03/msg00053.html If __USE_MINGW_ANSI_STDIO has not been defined when building GMP, then the length modifiers j, L and t are not supported with the GMP formatted output functions, and as a consequence, also with MPFR. This is automatically detected by the configure script, except when cross-compiling (e.g. under Linux), in which case some macros need to be defined explicitly, e.g. with "CPPFLAGS=-DNPRINTF_J -DNPRINTF_L -DNPRINTF_T" in order to avoid potential issues with the MPFR library and failures in the test suite (the corresponding tests are disabled explicitly). b. Using Cygwin =============== This build should be similar to that for MinGW except that the resulting library depends on the Cygwin DLL and cannot therefore be used with Visual Studio as with MinGW. Indeed, the binaries compiled with Cygwin require a dynamic library (cygwin.dll) to work; there is a Cygwin option -mno-cygwin to build native code, but it may require some non-portable tricks. In case of failure, you may need to pass LDFLAGS='-shared-libgcc' at the end of the configure line due to a bug in GCC. Otherwise, if threading support is not needed, you can configure MPFR with --disable-thread-safe. c. Using Microsoft Visual C++ and Intel C++ Compilers ===================================================== Static and dynamic MPFR libraries for the 32- and 64-bit versions of Windows can be built with Microsoft Visual Studio 2015 using the Microsoft Visual C++ compiler, see: https://visualstudio.microsoft.com/ The Intel C++ compiler provided as a part of Intel Parallel Studio XE can also be used: https://software.intel.com/en-us/parallel-studio-xe The relevant build projects are available here: https://github.com/BrianGladman d. Using the CompCert compiler ============================== [Tested with CompCert 3.10 and MPFR master-11992-f75b0c388 on x86_64-linux] CompCert (https://compcert.org/) is a formally verified compiler. To compile MPFR with CompCert: $ ./configure --disable-shared CC=ccomp CFLAGS="-flongdouble -fstruct-passing" You also need to unset LD_LIBRARY_PATH, and/or you might need to change wl="" into wl="-Wl," in the libtool file (after running configure). All tests (make check) should pass (tget_set_d64, tget_set_d128 and tset_float128 are skipped, since CompCert does not support _Decimal64, _Decimal128 nor _Float128). e. Using the Intel OneApi compiler ================================== When using the Intel OneApi compiler (icx), one should add -fp-model=strict to CFLAGS so that the conversion routines from/to native floating-point types (float, double, ...) work properly. Otherwise some tests will fail.