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<p>Thank you for the answer. We are using the Makefile from OpenSSL
to compile our feature as it changes OpenSSL directly. As I
understood it, we would have to import another number library to
compile our code with the standard OpenSSL settings and using the
logarithm, correct?</p>
<div class="moz-cite-prefix">On 2019-07-24 6:51 p.m., Guido Vranken
wrote:<br>
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cite="mid:CAO5O-EKCK743P0xeOvT5aP1btbtCiuMi1rGapzrciCjgx4daVA@mail.gmail.com">
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<div>If you want to use the log() from math.h, then you must
compile with -lm, eg.: clang source.c -lm</div>
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<div>The log() in math.h only supports floating point numbers.
If you require computing logarithms of bignums, try <a
href="https://www.mpfr.org/" moz-do-not-send="true">https://www.mpfr.org/</a></div>
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<div dir="ltr" class="gmail_attr">On Wed, Jul 24, 2019 at 6:39
PM Niklas Niere <<a
href="mailto:nniklas@mail.uni-paderborn.de"
moz-do-not-send="true">nniklas@mail.uni-paderborn.de</a>>
wrote:<br>
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<blockquote class="gmail_quote" style="margin:0px 0px 0px
0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">Hello,<br>
<br>
we are implementing a TLS 1.3 feature into OpenSSL to get an
idea of how <br>
well our feature performs in a concrete server library. In the
feature, <br>
we want to use the log function.<br>
<br>
When we try to use the log function from the math.h header,
OpenSSL <br>
won't compile with the statement that 'log' is a reference to
an <br>
undefined function. The BigNum library from OpenSSL does also
not seem <br>
to offer a log function.<br>
<br>
We suspect that the compile error comes from the fact that
OpenSSL is <br>
C90 compatible but are unsure. Does anyone know how to compute
the <br>
logarithm of a number in OpenSSL?<br>
<br>
Thanks,<br>
Niklas<br>
<br>
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