GNU MPFR version 3.1.1 (released on 3 July 2012)

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The canard à l'orange release, patch level 1.

MPFR 3.1.1 requires GMP 4.1.0 or higher (GMP 4.2.3 or higher is recommended).

Note: the bug-fix release MPFR 3.1.2 is available. Please upgrade!

Warning! Due to the fact that Thread-Local Storage (TLS) support is now detected automatically, the MPFR build can be incorrect on some platforms (compiler or system bug). Indeed, the TLS implementation of some compilers/platforms is buggy, and MPFR cannot detect every problem at configure time. Please run make check to see if your build is affected. If you get failures, you should try the --disable-thread-safe configure option to disable TLS and see if this solves these failures. But you should not use an MPFR library with TLS disabled in a multithreaded program (unless you know what you are doing).


The MPFR 3.1.1 source can be downloaded in the following archive formats:

MPFR is also available via third-party packages and ports.



The bugs listed below have been fixed (latest update: 2012-08-30). The patches are distributed under the same license as this version of MPFR, that is, the GNU Lesser General Public License (GNU Lesser GPL), version 3 or later.

The following instructions are for Linux and may be similar for other operating systems. You can apply the patches in several ways:

With the first two ways, the PATCHES file is modified, so that one can know what patches have been applied, using the mpfr_get_patches function. Moreover a suffix is added to the version string, but note that for practical reasons, not all the files where the version appears are patched; thus one can also track applied patches with the MPFR_VERSION_STRING macro (header) and the mpfr_get_version function (library). However, if some patches are not applied or if patches are applied in a different order, then the patch command will fail to update some chunks, so that the suffix is not always reliable for patches.

Note: These patches are in unified diff format and some vendors' patch commands cannot deal with them; in this case, please use GNU patch (it may already be installed on your system, e.g. as /usr/local/bin/patch or gpatch).

Fixed bugs, with patches:

  1. The mpfr_get_decimal64 function (available only when MPFR has been configured with --enable-decimal-float) has several bugs, fixed by the get_decimal64 patch, which also provides testcases. It corresponds to the following changesets in the 3.1 branch: 8373, 8378, 8380.
  2. The ternary value returned by the mpfr_strtofr function can be wrong under particular conditions (example). This is fixed by the strtofr-ternary-value patch, which also provides testcases. It corresponds to the following changeset in the 3.1 branch: 8399.
  3. MPFR 3.1.1 is not compatible with GMP 5.1.0 and later when the --with-gmp-build configure option is used. This is fixed by the gmp51-compat patch. It corresponds to the following changeset in the 3.1 branch: 8454.

Other bugs: please see the tracker and the BUGS file.

Changes from version 3.1.0 to version 3.1.1

Platforms Known to Support MPFR

MPFR 3.1.1 has been successfully compiled and checked on the following platforms:

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