morgan@ogicse.cse.ogi.edu (Clark O. Morgan) (05/15/91)
I noticed the other day that gcc (version 1.39) does not error
implicitly continued string constants (e.g., string constants that
contain actual newlines). This surprised me, because I personally
consider such strings to be programming typos, especially given the
alternatives available for continuing long strings (i.e., concatenation
or continuation with an explicit \n). I have been told that gcc is
ANSI C compatible.
So here's the question, is the following program legal ANSI C?
Script started on Wed May 15 00:43:44 1991
$ cat -n t.c
1 extern int printf(char *, ...);
2
3 int
4 main()
5 {
6 printf("junk);
7 string\n");
8 return (0);
9 }
$ gcc -Wall t.c <--- No complaints
$ a.out
junk);
string
$ exit
script done on Wed May 15 00:44:09 1991
Thanks in advance.henry@zoo.toronto.edu (Henry Spencer) (05/15/91)
In article <21455@ogicse.ogi.edu> morgan@ogicse.cse.ogi.edu (Clark O. Morgan) writes: >I noticed the other day that gcc (version 1.39) does not error >implicitly continued string constants (e.g., string constants that >contain actual newlines)... > >So here's the question, is the following program legal ANSI C? No. Newline is specifically excluded from the list of characters that can occur within an ANSI C string literal. You err in assuming that gcc is an ANSI C compiler, however. It will try to pretend to be one if you give the right magic combination of options, but by default it compiles something which is neither old C nor ANSI C. -- And the bean-counter replied, | Henry Spencer @ U of Toronto Zoology "beans are more important". | henry@zoo.toronto.edu utzoo!henry
rfg@NCD.COM (Ron Guilmette) (05/19/91)
In article <1991May15.155113.10624@zoo.toronto.edu> henry@zoo.toronto.edu (Henry Spencer) writes: +In article <21455@ogicse.ogi.edu> morgan@ogicse.cse.ogi.edu (Clark O. Morgan) writes: +>I noticed the other day that gcc (version 1.39) does not error +>implicitly continued string constants (e.g., string constants that +>contain actual newlines)... +> +>So here's the question, is the following program legal ANSI C? + +No. Newline is specifically excluded from the list of characters that +can occur within an ANSI C string literal. + +You err in assuming that gcc is an ANSI C compiler, however. It will try +to pretend to be one if you give the right magic combination of options, +but by default it compiles something which is neither old C nor ANSI C. There is nothing "magic" about it. Using the -pedantic and -ansi options causes GCC to complain about all violations of ANSI C (including the one being discussed here). If you are a pedant, you can install your copy of gcc so that these options are always on by default. -- // Ron ("Loose Cannon") Guilmette // Internet: rfg@ncd.com uucp: ...uunet!lupine!rfg // New motto: If it ain't broke, try using a bigger hammer.