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<title>GNU MPFR 3.1.5: Changed Functions</title>

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<p>
Next: <a href="Removed-Functions.html#Removed-Functions" accesskey="n" rel="next">Removed Functions</a>, Previous: <a href="Added-Functions.html#Added-Functions" accesskey="p" rel="prev">Added Functions</a>, Up: <a href="API-Compatibility.html#API-Compatibility" accesskey="u" rel="up">API Compatibility</a> &nbsp; [<a href="Concept-Index.html#Concept-Index" title="Index" rel="index">Index</a>]</p>
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<a name="Changed-Functions-1"></a>
<h3 class="section">6.3 Changed Functions</h3>

<p>The following functions have changed after MPFR 2.2. Changes can affect
the behavior of code written for some MPFR version when built and run
against another MPFR version (older or newer), as described below.
</p>
<ul>
<li> <code>mpfr_check_range</code> changed in MPFR 2.3.2 and MPFR 2.4.
If the value is an inexact infinity, the overflow flag is now set
(in case it was lost), while it was previously left unchanged.
This is really what is expected in practice (and what the MPFR code
was expecting), so that the previous behavior was regarded as a bug.
Hence the change in MPFR 2.3.2.

</li><li> <code>mpfr_get_f</code> changed in MPFR 3.0.
This function was returning zero, except for NaN and Inf, which do not
exist in MPF. The <em>erange</em> flag is now set in these cases,
and <code>mpfr_get_f</code> now returns the usual ternary value.

</li><li> <code>mpfr_get_si</code>, <code>mpfr_get_sj</code>, <code>mpfr_get_ui</code>
and <code>mpfr_get_uj</code> changed in MPFR 3.0.
In previous MPFR versions, the cases where the <em>erange</em> flag
is set were unspecified.

</li><li> <code>mpfr_get_z</code> changed in MPFR 3.0.
The return type was <code>void</code>; it is now <code>int</code>, and the usual
ternary value is returned.  Thus programs that need to work with both
MPFR 2.x and 3.x must not use the return value.  Even in this case,
C code using <code>mpfr_get_z</code> as the second or third term of
a conditional operator may also be affected. For instance, the
following is correct with MPFR 3.0, but not with MPFR 2.x:
<div class="example">
<pre class="example">  bool ? mpfr_get_z(...) : mpfr_add(...);
</pre></div>
<p>On the other hand, the following is correct with MPFR 2.x, but not
with MPFR 3.0:
</p><div class="example">
<pre class="example">  bool ? mpfr_get_z(...) : (void) mpfr_add(...);
</pre></div>
<p>Portable code should cast <code>mpfr_get_z(...)</code> to <code>void</code> to
use the type <code>void</code> for both terms of the conditional operator,
as in:
</p><div class="example">
<pre class="example">  bool ? (void) mpfr_get_z(...) : (void) mpfr_add(...);
</pre></div>
<p>Alternatively, <code>if ... else</code> can be used instead of the
conditional operator.
</p>
<p>Moreover the cases where the <em>erange</em> flag is set were unspecified
in MPFR 2.x.
</p>
</li><li> <code>mpfr_get_z_exp</code> changed in MPFR 3.0.
In previous MPFR versions, the cases where the <em>erange</em> flag
is set were unspecified.
Note: this function has been renamed to <code>mpfr_get_z_2exp</code>
in MPFR 3.0, but <code>mpfr_get_z_exp</code> is still available for
compatibility reasons.

</li><li> <code>mpfr_strtofr</code> changed in MPFR 2.3.1 and MPFR 2.4.
This was actually a bug fix since the code and the documentation did
not match.  But both were changed in order to have a more consistent
and useful behavior.  The main changes in the code are as follows.
The binary exponent is now accepted even without the <code>0b</code> or
<code>0x</code> prefix.  Data corresponding to NaN can now have an optional
sign (such data were previously invalid).

</li><li> <code>mpfr_strtofr</code> changed in MPFR 3.0.
This function now accepts bases from 37 to 62 (no changes for the other
bases).  Note: if an unsupported base is provided to this function,
the behavior is undefined; more precisely, in MPFR 2.3.1 and later,
providing an unsupported base yields an assertion failure (this
behavior may change in the future).

</li><li> <code>mpfr_subnormalize</code> changed in MPFR 3.1.
This was actually regarded as a bug fix. The <code>mpfr_subnormalize</code>
implementation up to MPFR 3.0.0 did not change the flags. In particular,
it did not follow the generic rule concerning the inexact flag (and no
special behavior was specified). The case of the underflow flag was more
a lack of specification.

</li><li> <code>mpfr_urandom</code> and <code>mpfr_urandomb</code> changed in MPFR 3.1.
Their behavior no longer depends on the platform (assuming this is also true
for GMP&rsquo;s random generator, which is not the case between GMP 4.1 and 4.2 if
<code>gmp_randinit_default</code> is used).  As a consequence, the returned values
can be different between MPFR 3.1 and previous MPFR versions.
Note: as the reproducibility of these functions was not specified
before MPFR 3.1, the MPFR 3.1 behavior is <em>not</em> regarded as
backward incompatible with previous versions.

</li></ul>

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