Const and Optimization in C

Re:Const and Optimization in C by QuadrupleA on Monday July 25, 2016 @12:45PM (#12159866)

I've personally stopped using const in my C and C++ code, except for actually defining constants (in the #define sense). The headaches and complexity it introduces don't seem worth the benefit - you inevitably have to remove the const modifiers from your "const correct" function at some point when it needs to calls out to a non-const function you don't control (one that you know is 'logically const' and pure but doesn't declare it as such in the signature). And as this article demonstrates, the benefits to optimization are not always that great.

And with any kind of STL-like interface or container you're suddenly maintaining two duplicate versions of everything, a non-const version and a const version, likely along with a confusing pile of template metaprogramming and typedefs to support that. Avoiding const altogether is much cleaner.

As Casey Muratori (game programmer) once said, "I haven't typed "const" in over a decade, and I have had literally zero bugs that it would have caught."

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Re:Const and Optimization in C by jjnoakes on Monday July 25, 2016 @12:56PM (#12159936)

I feel like this is analogous to throwing the baby out with the bath water.

I think writing const-correct code where you can is useful. It helps document your code (for yourself and for others), it CAN catch issues (even if Casey Muratori claims it never helped), and it really isn't that hard to do (C routines don't need to be duplicated if you want to return non-const, like strstr, for example).

So what if you have to cast-away-const for interfacing to libraries which aren't const-correct? It still has benefits for your own code.

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