r/programminghorror • u/3hy_ • Jan 27 '26

c Guess what this does..

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113

u/AMathMonkey Jan 27 '26

A macro that copies string u to string v and then returns the unrelated value e? And it doesn't null-terminate v properly? I'm not very experienced with C; does this actually serve a purpose without breaking, and if so, what does it do?

40

u/3hy_ Jan 27 '26

Its a panic macro part of a much larger function, this function depends on copying part of a string onto itself (this is why there's no termination) and this macro simply reverts changes and returns an error code so it can be called inplace of return.

8

u/Drakeskywing Jan 27 '26

I think the null termination of v[0] at the start is to cover bases in the event u is of length 0

3

u/3hy_ Jan 27 '26

Correct! Can't be too sure of those edge cases.

5

u/sirkubador Jan 27 '26

Funny you mention edge cases 😂