nbdkit_parse_probability(3)

📦
version 1.48.1 · 10 versions
, in fedora 44

💖 nbdkit_parse_probability 💖

okay bestie, welcome to nbdkit_parse_probability(3) — the little utility that turns your chaotic probability strings into actual numbers. no cap, it's a lifesaver.

✨ NAME ✨

nbdkit_parse_probability — parse probabilities for nbdkit 🎀

✨ SYNOPSIS ✨

#include <nbdkit-plugin.h>

int nbdkit_parse_probability (const char *what, const char *str,
                              double *ret);

✨ DESCRIPTION ✨

so basically, you call nbdkit_parse_probability when you need to parse probabilities, and it just gets you. it understands all the common formats, like:

  • 0.1
  • 1e-1
  • 10%
  • 1:10
  • 1/10

…and every single one of those means a probability of 1 in 10. iconic, honestly. 🌈

The what parameter is the thing that gets printed in error messages, so it gives peeps some context about what was being parsed. and str is the probability string itself. that's it, that's the whole vibe. ✨

✨ RETURN VALUE ✨

On success, the function returns 0. and if ret != NULL, it sets *ret to the parsed value. but if ret == NULL? the parsing still happens, the result just gets thrown away. lowkey ghosted. 💀

The probability is always a finite number ≥ 0.0, but heads up: the result can totally be larger than 1.0. like, if str == "200%" then the function sets *ret = 2.0. so if you want to clamp the upper bound, the caller has to do that themselves. it's giving "not my job". 🙈

On error, nbdkit_error(3) gets called and -1 is returned. and on error, *ret is always unchanged — no sneaky edits, periodt.

ngl the "always unchanged on error" thing is a genuinely thoughtful design choice and I'm obsessed with it. 🫶

✨ LANGUAGE BINDINGS ✨

💜 In nbdkit-ocaml-plugin(3)

NBDKit.parse_probability : string -> string -> float

💜 In nbdkit-python-plugin(3)

import nbdkit
size = nbdkit.parse_probability(what, str)

💜 In nbdkit-rust-plugin(3)

use nbdkit::*;
pub fn parse_probability(what: &str, s: &str) -> Result<f64>

✨ HISTORY ✨

nbdkit_parse_probability was added in nbdkit 1.36. so it's not even that old, it's a baby. 👑

✨ SEE ALSO ✨

✨ AUTHORS ✨

Richard W.M. Jones 💅

Copyright Red Hat

✨ LICENSE ✨

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

  • Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
  • Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
  • Neither the name of Red Hat nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

okay that's the whole page, we ate and left no crumbs 🍓✨

this was nbdkit-1.48.1, dated 2026-08-29, and it's the nbdkit_parse_probability(3) page — bye bestie, go parse some probabilities 💖🦋

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