RealView Compilation Tools Compiler Reference Guide - ARM ...

C and C++ Implementation Details
the integer value. The last character in the constant occupies the lowest-order byte
of the integer value. Up to three preceding characters are placed at higher-order
bytes. Unused bytes are filled with the NULL (\0) character.
• Table 5-1 lists all integer character constants, that contain a single character or
character escape sequence, are represented in both the source and execution
character sets.
Table 5-1 Character escape codes
Escape sequence Char value Description
\a 7 Attention (bell)
\b 8 Backspace
\t 9 Horizontal tab
\n 10 New line (line feed)
\v 11 Vertical tab
\f 12 Form feed
\r 13 Carriage return
\xnn 0xnn ASCII code in hexadecimal
\nnn 0nnn ASCII code in octal
• Characters of the source character set in string literals and character constants
map identically into the execution character set.
• Data items of type char are unsigned by default. They can be explicitly declared
as signed char or unsigned char:
— the --signed_chars option can be used to make the char signed
— the --unsigned_chars option can be used to make the char unsigned.
Note
Care must be taken when mixing translation units that have been compiled with
and without the --[un]signed chars option, and that share interfaces or data
structures.
The ARM ABI defines char as an unsigned byte, and this is the interpretation used
by the C++ libraries supplied with RVCT.
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