No, __LINE__ is perfectly good C90. (Or else I wouldn't have used it in my coroutines trick – my original invention of that predated C99 by several years, and Tom Duff said he'd thought of the same thing much, much earlier.)
I don't see how it helps you here, though. It surely can't save you from thread-safety issues, because it won't have a distinct value in each thread?
Thank you. I don't think I quite thought through what i did want. But i think that where I'm going is that if you want to use a function to represent the "compare el against head, except ignore the first and every second match" logic instead of a simple local var, it needs to identify when its part of the same loop and when it isn't, which it might be able to do with a combination of (a) using some thead local storage or thread id to maintain when the next call is from the same thread and (b) using a line directive to determine when its called from different (nested) places in the same file and thread.
Your solution is probably right because it uses syntax to resolve a problem with insufficiently expressive syntax. Whereas mine (if it worked) would be how to solve a problem if the constraints here were logical parts of the program for some reason.
I agree it's horrendous, that's why i recommend using a language with convenient local variables, fewer macros, etc, etc :)
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__LINE__is perfectly good C90. (Or else I wouldn't have used it in my coroutines trick – my original invention of that predated C99 by several years, and Tom Duff said he'd thought of the same thing much, much earlier.)I don't see how it helps you here, though. It surely can't save you from thread-safety issues, because it won't have a distinct value in each thread?
Thank you. I don't think I quite thought through what i did want. But i think that where I'm going is that if you want to use a function to represent the "compare el against head, except ignore the first and every second match" logic instead of a simple local var, it needs to identify when its part of the same loop and when it isn't, which it might be able to do with a combination of (a) using some thead local storage or thread id to maintain when the next call is from the same thread and (b) using a line directive to determine when its called from different (nested) places in the same file and thread.
Your solution is probably right because it uses syntax to resolve a problem with insufficiently expressive syntax. Whereas mine (if it worked) would be how to solve a problem if the constraints here were logical parts of the program for some reason.
I agree it's horrendous, that's why i recommend using a language with convenient local variables, fewer macros, etc, etc :)