GNU libiconv

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Mostly written in C

License: gpl

AltIO   (Compare Project)

License: gpl3

Tetengo2   (Compare Project)

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License: gpl3

GNU C Library   (Compare Project)

Mostly written in C

License: lgpl

GNU Libtool   (Compare Project)

Mostly written in C

License: gpl

GnuTLS   (Compare Project)

Mostly written in C

License: gpl3_or_later, lgpl21_or_later

GNU Octave   (Compare Project)

License: gpl3_or_later

GSL - GNU Scientific Library   (Compare Project)

Mostly written in C

License: gpl3_or_later

libgcrypt   (Compare Project)

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License: lgpl21_or_later

GNU Classpath   (Compare Project)

License: GPL-2-0-with-classpath-exception