RE: [avr-gcc-list] Re: Strings: escape sequence to insert arbitrary hex value ?

[Dave Hansen]

 From: address@hidden
[...]
>
>> ISO C99, section 6.4.4.4, p3:
>> the question-mark ?, [..] is representable according to the following table 
>> of escape
>> sequences: question mark? \?
>
> Interesting. I wonder why the standard deeemd it necessary to provide
> an escape sequence for the question mark ?
 
As other have mentioned, it's to prevent the substitution of trigraphs.  
Trigraphs are a way to express characters that either do not appear is the 
source character set, or are handled poorly by the development environment.  If 
trigraphs are enabled, then
 
   puts("Trigraphs??!");
 
will output "Trigraphs|" (IIRC).  To prevent this, you can use
 
   puts("Trigraphs?\?!");
 
Regards,
 
   -=Dave
 
 

 
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