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Why do libraries define their own true and false?
(pawb.social)
I’m working through the vulkan tutorial and came across GLFW_TRUE and GLFW_FALSE. I presume there’s a good reason but in looking at the docs it’s just defining 1 and 0, so I’m sorta at a loss as to why some libraries do this (especially in cpp?).
Tangentially related is having things like vk_result which is a struct that stores an enum full of integer codes.
Wouldn’t it be easier to replace these variables with raw int codes or in the case of GLFW just 1 and 0?
Coming mostly from C, and having my caps lock bound to escape for vim, the amount of all caps variables is arduous for my admittedly short fingers.
Anyway hopefully one of you knows why libraries do this thanks!
It's because the Booleans sometimes are flipped in display-server technology from the 1980s, particularly anything with X11 lineage, and C didn't have Boolean values back then. More generally, sometimes it's useful to have truthhood be encoded low or 0, as in common Forths or many lower-level electrical-engineering protocols. The practice died off as popular languages started to have native Boolean values; today, about three quarters of new developers learn Python or ECMAScript as their first language, and FFI bindings are designed to paper over such low-level details. You'll also sometimes see newer C/C++ libraries depending on newer standards which add native Booleans.
As a fellow vim user with small hands, here are some tricks. The verb
gUwill uppercase letters but not underscores or hyphens, so sentences likegUiwcan be used to uppercase an entire constant. The immediate action~which switches cases can be turned into a verb by:set tildeop, after which it can be used in a similar way togU. If constants are all namespaced with a prefix followed by something unique like an underscore, then the prefix can be left out of new sections of code and added back in with a macro or a:%sreplacement.In VisualBasic "true" would be represented as -1 when converted to an int because it's all 1's in twos complement.
By the way, you can use
g~to get the effects of tildeop without needing to set it.Seriously helpful thanks! One of my friends working on a G15 restoration project pointed out this notation to be after you did— yet while they use 0 for truth they used 20 for false so not sure were they got the second idea. And your vim tip saved me a bunch of hand ache!