mktime() gives different UTC results for the same local time across C libraries — which behavior is correct?
Goal I need portable date conversion in C using only <time.h> : given a broken-down local time in a struct tm , convert it to time_t with mktime() and later recover the same wall-clock time with localtime() . The target zone is selected through the TZ environment variable plus tzset() on POSIX systems. Constraint My understanding is that when a local t
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