2.2.5 Attributes and Qualifiers
The compiler keyword __attribute__
allows you to specify
special attributes of variables, structure fields or functions. This keyword is followed by
an attribute specification inside double parentheses, as in:
int last_mode __attribute__ ((persistent));
In other compilers, qualifiers are used to create qualified types:
persistent int last_mode;
The MPLAB XC16 C Compiler does have some non-standard qualifiers described in Compiler-Specific Type Qualifiers
Generally speaking, qualifiers indicate how an object should be accessed, whereas attributes indicate where objects are to be located. Attributes also have many other purposes.