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by api
3646 days ago
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0 == true is also used in C error return values, where nonzero means "false" as in "did not succeed." So it's not without precedent. It's not a terrible idea. In most types of computing there's often only one way for something to be true but N ways for it to be false. |
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The C language and the standard library are distinct things. C originally did not define any values at all for booleans (true / false), but later implementations did and even in the oldest C compilers (0 == 0) would evaluate to '1', which caused the most repeated lines of C preprocessor input ever written:
#define TRUE 1 #define FALSE 0
Guarded by some #ifdefs if your compiler supported that.
Some standard library functions return nonzero on error (which can be < 0 or > 0), zero on 'success' which is not the same as true, and others (annoyingly) return 1 on 'success' or 'true' (such as the isalpha function/macro).