Any decent compiler should optimize that line away (GCC does at its default optimization level). So while odd, it really shouldn't affect anything.

This library is a little too simple. A true PPM image should be saved using the BT.709 colorspace. This library merely dumps the RGB array given to it to a PPM like formatted file. Seeing as most systems today usually assume a sRGB colorspace (unless told otherwise) you will likely be writing an incorrect format to the PPM file using this library. Just a heads up to anyone trying to use this.

Code from a colleague:

% The following setting should never be 0
setting=0;

I was doing some calculations for my research and I needed more precision than afforded by the long float type

Using 'long double' on a x86 machine should give you access to 80 bit FP math (as supported by the x87 FPU instructions). Unfortunately x87 and SSE instructions are mutually exclusive (SSE instructions only support 64bit doubles) so there may be a performance hit (although 80bit x87math is still a heck of a lot faster than extended precision software implementations).

Except use of the Numberical Recipes algorithms is not free. You are not allowed to you use their algorithms in anything that is distributed by source (so forget any GPL'd code). You are not allowed to distribute binaries that exposes the algorithms (I believe the intent is to prevent someone from distributing a "NR library" but the wording is ambiguous enough that a bunch of other implementations could be caught). Commercial distribution requires a institutional subscription (and must still comply with the no source code, no API conditions).

In general I advise all programers to avoid reading Numerical Recipes. It's a minefield of copyright infringement and just not worth the risk.

Yes, the perpetual license model is for the starting version but I don't see how that is any different than what they provide today with the "standard" license model. If you buy the application today you get to keep that version perpetually. If you don't decide to upgrade after a year you are still stuck with a 1 year old version. You can achieve this with the subscription model by just purchasing an annual subscription day one (which from what I can tell is actually cheaper than the current "full" license). At anytime you want to leave you can just do a last time annual purchase (they should just offer a buyout option) and keep that version indefinitely (and with loyalty discount that last time purchase is probably as cheap or cheaper than the current upgrade charge).

Now the problem that I do see with all this is bug fixes. I'm not sure how JetBrain's does this (I don't use them) but usually bug fixes for a particular version are freely distributed. Only new features constitute an upgrade. Now with the subscription model I don't know how they will handle this. Why maintain version specific bug fixes when you're using a rolling deployment model. This to me is a very real issue they haven't addressed.

Edit: Looks like "3rd" digit bug fixes are included in the perpetual license. From the blog:

2) will the fallback license grant me the permission to also use all subsequential minor versions, or it will be valid only for a current major+minor version released at the time of subscribing?

Maxim Shafirov says: September 18, 2015 at 2:44 pm

2) Bugfix releases are included. More specifically, 3rd digit versions.