{"id":830,"date":"2021-09-09T14:35:00","date_gmt":"2021-09-09T12:35:00","guid":{"rendered":"https:\/\/www.dereckson.be\/blog\/?p=830"},"modified":"2025-09-26T20:21:29","modified_gmt":"2025-09-26T18:21:29","slug":"iec-559-support-in-libtommath-on-freebsd","status":"publish","type":"post","link":"https:\/\/www.dereckson.be\/blog\/2021\/09\/09\/iec-559-support-in-libtommath-on-freebsd\/","title":{"rendered":"IEC 559 support in LibTomMath on FreeBSD"},"content":{"rendered":"\n

Raku is the new name of Perl 6, a language inspired by Perl and compiled for a virtual machine. When preparing FreeBSD ports for the Raku ecosystem, I’ve noticed those depend on LibTomMath<\/a>, with IEEE754<\/a> floating point format support.<\/p>\n\n\n\n\n\n\n\n

Let’s try to call zef, a tool to manage modules (dependencies) in Raku:<\/p>\n\n\n\n

$ raku \u2026 zef \u2026
ld-elf.so.1: \/\/usr\/local\/lib\/libmoar.so: Undefined symbol \"mp_set_double\"<\/code>
(MoarVM<\/a> is the virtual machine running the Raku bytecode)<\/p>\n\n\n\n

When building the port:
bn_mp_set_double.c:44:6: warning: \"mp_set_double implementation is
only available on platforms with IEEE754 floating point format\"
[-W#warnings]<\/code><\/p>\n\n\n\n

The source code protects mp_set_double function with a check for
STDC_IEC_559<\/strong> defined.<\/p>\n\n\n\n

This is well supported by the OS, as documented in man 3 ieee<\/a>, but the compilers clang and gcc don’t seem to define it. On the Linux platform, glibc defines it. <\/p>\n\n\n\n

The library refactored the way to detect STDC_IEC_559<\/a>, but this isn’t released yet.<\/p>\n\n\n\n

Pietro Cerutti, who maintains the FreeBSD port for LibTomMath, merged this better detection patch<\/a>, so we can benefit of those features right now.<\/p>\n\n\n\n

So you can know use mp_set_double<\/code> on FreeBSD machines too, and the zef package manager.<\/p>\n\n\n\n

Related links<\/p>\n\n\n\n