Re: [avr-gcc-list] avr-gcc does not throw diagnostics on undefined escape sequences

[Georg-Johann Lay]

Jan Waclawek schrieb:
> The following code:
>
> #include <stdio.h>
>
> int a = 1; int b = 1; int c = 1; int d = 1; int e = 1; int f = 1;
>
> char buffer[30];
>
> int main(void) { sprintf(buffer, "\%d/\%d/\%02d \%d:\%02d:\%02d", a,
> b, c, d, e, f); printf(buffer); }
>
>
> compiles cleanly with avr-gcc (I tried both 4.2.2 and 4.7.1), even
> with -std=c99.

const char c[] = "\%";

compile

$ gcc file.c -std=c99 -fsyntax-only -pedantic-errors

file.c:1:18: unknown escape sequence '\%'

Tested with gcc 3.4 and gcc 4.7

> My understanding of C99, 6.4.4.4, especially footnote 65, indicates,
> that the \% sequence should result in compiler error.

Yes.

> Comments, please?

Read "C Dialect Options" and what -std=c99 means

http://gcc.gnu.org/onlinedocs/gcc/C-Dialect-Options.html

Johann