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Trio Competitors

While Trio is a very competent and feature-packed library, you may not like it. Then try one of these free alternatives:

  • Vstr library by James Antill. LGPL-licensed and very standard conforming string library, include printf() and family.
  • Str library by Ralf S. Engelschall, BSD-style license. This is based on the Apache's snprintf, that in turn is based on the SIO routines. Does not seem to support positional n$-arguments (even though the docs claim so).
  • snprintf.c by Mark Martinec, Frontier Artistic License (similar to the Artistic License). Does not support: n$-arguments, numeric conversion specifiers: f, e, E, g, G and synonym F, as well as the new a and A conversion specifiers, length modifier 'L' (long double) and 'q'
  • Sfio by Glenn Fowler, David Korn, and Kiem-Phong Vo. The license is BSD-stylish, but you must fill in their web form!
  • SIO by Panos Tsirigotis - web page? - license? Used in Apache
  • snprintfv by Gary v. Vaughan, GPL license. provides all the features present in a POSIX format printing implementation, such as guaranteed return of number of characters printed and support for %n$ format specifiers.
  • libutf8 contains its own implementation of the printf/wprintf functions. No scanf functions though.
  • Holger Weiss' snprintf is based on Patrick Powell's implementation. "with a lot of features added and various bugs fixed, so that it should now support everything from C99 (plus the "'" flag) except for "%a/%A" conversions and wide characters."

And if you don't like this comparison, here's another printf() implementation comparison.

Web page edited by daniel at, modified January 08, 2008