The Atari ST and the Macintosh both used Motorola's 68000 microprocessor, so it makes sense that the same assemblers and compilers could be used for both, but I can't be entirely certain that Hippo-C ran natively on the Macintosh, as opposed to being a cross-compiler for the platform. Most of what I can find discusses it in relation to the Atari ST, for which it was also available.

I find a few editions of InfoWorld offering it for sale, one off-handed mention of it in a November 1984 MUG newsletter ('…how about your impressions of the various development environments…Is Hippo C any good, or what?'), but no reviews of it in Macintosh magazines. However, I can find vanishingly little information online about Hippo-C. This is pretty compelling evidence that Hippo-C was the first C compiler for the Mac, available at the computer's launch. Plus, Jobs is wearing a silver bow-tie in the picture, which looks like the same one he wore that fateful day at Apple's Annual Shareholders Meeting. Macintosh was introduced to the world on January 24, 1984, and even if Brown had held a separate launch event a few days later for his C compiler, I doubt he could have persuaded Steve Jobs to show up. (Image courtesy of Carol Rukomii Holladay, via Wikipedia, licensed under CC by-SA.) The Wikipedia article on Brown has the following picture, showing him with Steve Jobs, with the caption claiming that the picture was taken 'at the launch of Brown's Hippo-C software for Macintosh, January 1984': Hippo-CĪs far as I can tell, the very first C compiler ever released for the Macintosh was Hippo-C, developed by Wendell Brown, the founder of Hippopotamus Software. All of these compilers were available on other platforms, too, especially the Atari ST. Other early options included Manx Software's Aztec C (see also this site), Megamax C, and Softworks C ( which Kevin Killion claims was 'the very first C language compiler for the Mac', for which he wrote the front-end, but I cannot find independent verification for this claim).

The two earliest C compilers available for Macintosh were Hippo-C and Consulair Mac C.

C was merely a niche language in 1984, and I doubt very many copies of these were sold, but that doesn't mean you didn't have choices! The Macintosh's System Software and ROMs were themselves programmed largely in assembly, with a bit of Pascal thrown in (mostly for pieces that were ported directly from the Lisa). As you said, the most important languages on the Mac in its early days were Microsoft's BASIC, Pascal, and, of course, 68000 assembly.

C compiler macos