Path: csiph.com!weretis.net!feeder6.news.weretis.net!news.misty.com!news.iecc.com!.POSTED.news.iecc.com!nerds-end From: gah4 Newsgroups: comp.compilers Subject: Re: C and Java, was Compilers :) Date: Fri, 13 Jan 2023 12:39:41 -0800 (PST) Organization: Compilers Central Sender: news@iecc.com Approved: comp.compilers@iecc.com Message-ID: <23-01-054@comp.compilers> References: <23-01-001@comp.compilers> <23-01-007@comp.compilers> <23-01-051@comp.compilers> <23-01-053@comp.compilers> MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Injection-Info: gal.iecc.com; posting-host="news.iecc.com:2001:470:1f07:1126:0:676f:7373:6970"; logging-data="18371"; mail-complaints-to="abuse@iecc.com" Keywords: C, Java Posted-Date: 13 Jan 2023 16:19:24 EST X-submission-address: compilers@iecc.com X-moderator-address: compilers-request@iecc.com X-FAQ-and-archives: http://compilers.iecc.com In-Reply-To: <23-01-053@comp.compilers> Xref: csiph.com comp.compilers:3322 On Friday, January 13, 2023 at 11:10:37 AM UTC-8, gah4 wrote: (snip) > Some time ago, I was trying to figure out if you could make a C compiler > that generated JVM code. I would run much closer to the C standard > than much C code does, especially regarding casting of pointers. > [So what did you conclude? I'd think C type casts would be hard to > turn into Java unless you made all of storage an opaque block. -John] Someone else might have thought about the "opaque block" method. But that wouldn't work if you wanted to call between Java and C. As well as I know it, C only requires assignment to work for pointers cast to (unsigned char *). And once they are cast, usually (though I suppose not always), it is done with memcpy(), or compared with memcmp(). So, all the complication of figuring out what is actually being done, can be done inside one of those. C pointers, then, are an object with a reference to the actual array, and current offset within the array, and bounds for the array. Pointer arithmetic only changes the offset. Scalar variables that can be pointed to, compile as arrays dimensioned [1]. I didn't get as far as figuring out varargs functions, but someone must have done that, as System.out.format() works. You can call it with the usual different argument types, and it figures out everything.