C init preprocessor array

Question

I am writing a complex macro and I need to pass in an array initializer as well. Basically I have problems:

#define INIT_ARR(VAR_NAME,ARR_DATA) int VAR_NAME[] = ARR_DATA

then I would call him

INIT_ARR(myNm,{1,2,3});

but the preprocessors interpret any commas (also inside inside curly braces) as a new macro parameter, so it gives me an error:

error:  #55-D: too many arguments in invocation of macro "INIT_ARR"

Preprocessor

doesn't ignore (), so I can do:

#define INIT_ARR(VAR_NAME,ARR_DATA) int VAR_NAME[] = {ARR_DATA}
INIT_ARR(myNm,(1,2,3));

but then it is interpreted as

int myNm[] = {(1,2,3)};

which is not true for C.

Is there a way how to do this? For example, remove the curly braces from the parameter?

+3

Vit Bernatik Jul 26 17 at 11:18

2 answers

You can use a variable number of arguments with a macro as -

#define INIT_ARR(VAR_NAME, ...) int VAR_NAME[] = {__VA_ARGS__}

+6

Ajay brahmakshatriya Jul 26 17 at 11:22

Vit Bernatik · Accepted Answer · 2017-07-26T11:42:08+0000

I think I hacked it:

#define myArgs(...) __VA_ARGS__
#define INIT_ARR(VAR_NAME,ARR_DATA) int VAR_NAME[] = {myArgs ARR_DATA}
INIT_ARR(myArr,(1,2,3,4));

will be correctly interpreted as:

int myArr[] = {1,2,3,4};

annoying_squid's answer helped me figure it out ...