Why do Objective-C files use the .m extension?

objective-c file-extension
Kuba Suder picture Kuba Suder · Mar 16, 2009 · Viewed 71.5k times · Source

Since I started learning Objective-C and Cocoa, I've been wondering why they have chosen the extension .m for the implementation files - was it supposed to mean something, or was it just a random letter?

Answer

splattne picture splattne · Mar 16, 2009

Today most people would refer to them as "method files", but

"The .m extension originally stood for "messages" when Objective-C was first introduced, referring to a central feature of Objective-C [...]"

(from the book "Learn Objective-C on the Mac" by Mark Dalrymple and Scott Knaster, page 9)

EDIT: To satisfy an itch I emailed Brad Cox, the inventor of Objective-C, about the question and he answered with this single line:

"Because .o and .c were taken. Simple as that."

Here's the email as visual proof:

Visual Proof

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