Why is FILE all-caps as in FILE*? [closed]

Question

This just seems odd to me, most other things are lower case.

Is there some historical reason?

Answer 1

It's a macro. Macros have historically had all caps in C. Unfortunately recent trends appear to have broken that fact.

Small history lesson: Also, FILE was an io buffer abstraction in UNIX v7 libc stdio. A FILE doesn't necessarily represent a physical file, just something that can do block IO. Source:

http://www.bsdlover.cn/study/UnixTree/V7/usr/include/stdio.h.html

"file" was already defined by the kernel as well:

http://www.bsdlover.cn/study/UnixTree/V7/usr/include/sys/file.h.html

As someone else said here it's probably a typedef now, but I don't think C had typedefs back in '79 as it only just had structs. Then again I wasn't born then so... :)

Answer 2

It's all caps almost certainly because at least originally it was a macro. Nowadays, chances are pretty good that it's a typedef instead, but nobody changed the name to boot (and doing so would be a pretty lousy idea).