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

[Jan Waclawek]

>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
>


Indeed. So, this particular "error" is revealed only if -pedantic-whatever is 
used.

One learns something new every day. Thanks, Johann.



Meantime, I also consulted the Derek Jones book, which for this particular 
issue says, among other interesting things, this:

"It is possible that an occurrence of such a character sequence will cause a 
violation of syntax to occur,
which will in turn require a diagnostic to be generated. However, 
implementations are not required to issue a
diagnostic just because a footnote (which is not non-normative) says one is 
required."

Two new things learned today... :-)



Jan