Date: Mon, 21 Feb 2005 18:59:51 +0200 From: Giorgos Keramidas <keramida@ceid.upatras.gr> To: Kathy Quinlan <kat-free@kaqelectronics.dyndns.org> Cc: freebsd-hackers@freebsd.org Subject: Re: Error in my C programming Message-ID: <20050221165951.GA2124@gothmog.gr> In-Reply-To: <4219C912.2070207@kaqelectronics.dyndns.org> References: <4218B960.1050403@kaqelectronics.dyndns.org> <20050220183219.GK57256@cirb503493.alcatel.com.au> <4218DEC5.1080600@kaqelectronics.dyndns.org> <20050221065844.GB81063@cirb503493.alcatel.com.au> <4219C912.2070207@kaqelectronics.dyndns.org>
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On 2005-02-21 19:42, Kathy Quinlan <kat-free@kaqelectronics.dyndns.org> wrote: > Peter Jeremy wrote: > > OK it was all to do with the comments it did not like the //comments > ARRGGHHHH the rest of the errors were bogus as soon as I changed EVERY > comment over to the ANSI C /*comments*/ it now works (oh and removed the > #pragma directives from a c compiler for the AVR uC I will have to put > all the different complier directives in different #ifdef tags :) The quotations seem a bit messed up, so I don't know if Peter Jeremy or Kathy Quinlan wrote the above paragraph. Whoever the author was though, it may be worth to note that C99 *does* allow single-line comments delimited by //. The correct way to invoke the C compiler in C99-mode depends, of course, on the compiler and it enables far more features than // comments. For GCC, the correct option to use is -std=c99. Using this program as a test, you can check for yourself (note that the comments of the sort shown in the following program are EXTREMELY bad style; they only serve as a test for //-style comments): $ cat -n foo.c 1 #include <stdio.h> // For printf() 2 #include <stdlib.h> // For EXIT_SUCCESS 3 4 int 5 main(void) 6 { 7 printf("Hello C99 world\n"); // Print a message. 8 return (EXIT_SUCCESS); // Terminate program. 9 } Compiling in C89 mode (which does not allow // comments) gives: $ gcc -O -Wall -std=c89 foo.c foo.c:1:23: warning: extra tokens at end of #include directive foo.c:2:24: warning: extra tokens at end of #include directive foo.c: In function `main': foo.c:7: error: syntax error before '/' token $ Compiling in C99 mode, works as expected: $ gcc -O -Wall -std=c99 foo.c $ ./a.out Hello C99 world $
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