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Re: [avr-gcc-list] C Escape sequence.
From: |
Joerg Wunsch |
Subject: |
Re: [avr-gcc-list] C Escape sequence. |
Date: |
Thu, 25 May 2006 08:10:32 +0200 (MET DST) |
"Royce Pereira" <address@hidden> wrote:
> Sorry for my rusty C, but how does one insert a hex value into a string?
> I tried
> const char messg[] PROGMEM= "Temp= \xdfC";
> and
> const char messg[] PROGMEM= "Temp= \xdf\C";
That's the exact reason why C89 invented the feature to concatenate
adjacent strings into one. You can write
const char messg[] PROGMEM= "Temp= \xdf" "C";
Or, you could improve readability by
#define DEGREE "\xdf"
...
const char messg[] PROGMEM= "Temp= " DEGREE "C";
Hexadecimal or octal escape sequences stop at the first character that
does not belong to their respective character set, that's why your
first variant didn't work (the "C" is a valid hex character). In
traditional K&R C, there were no hexadecimal escape sequences, and
IIRC octal escape sequences artificially stopped after the third octal
digit.
--
cheers, J"org .-.-. --... ...-- -.. . DL8DTL
http://www.sax.de/~joerg/ NIC: JW11-RIPE
Never trust an operating system you don't have sources for. ;-)