User manual

mikroC PRO for dsPIC

MikroElektronika

263

Preprocessor Operators

The # (pound sign) is a preprocessor directive when it occurs as the rst non-whitespace character on a line. Also, #

and ## perform operator replacement and merging during the preprocessor scanning phase.

Operator #

In C preprocessor, a character sequence enclosed by quotes is considered a token and its content is not analyzed. This

means that macro names within quotes are not expanded.

If you need an actual argument (the exact sequence of characters within quotes) as a result of preprocessing, use the #

operator in macro body. It can be placed in front of a formal macro argument in denition in order to convert the actual

argument to a string after replacement.

For example, let’s have macro LCD_PRINT for printing variable name and value on Lcd:

#dene LCD_PRINT(val) Lcd_Out_Cp(#val “: “); \

Lcd_Out_Cp(IntToStr(val));

Now, the following code,

LCD_PRINT(temp)

will be preprocessed to this:

Lcd_Out_Cp(“temp” “: “); Lcd_Out_Cp(IntToStr(temp));

Operator ##

Operator ## is used for token pasting. Two tokens can be pasted(merged) together by placing ## in between them

(plus optional whitespace on either side). The preprocessor removes whitespace and ##, combining the separate

tokens into one new token. This is commonly used for constructing identiers.

For example, see the denition of macro SPLICE for pasting two tokens into one identier:

#dene SPLICE(x,y) x ## _ ## y

Now, the call SPLICE(cnt, 2) will expand to the identier cnt_2.

Note: The mikroC PRO for dsPIC30/33 and PIC24 does not support the older nonportable method of token pasting

using (l/**/r).