Rif.: CVI2013 f1 and preprocessor ## directive

[vix]

CVI2013 with f1 gives build error for preprocessor ## directive (token concatenation).

See attachment

[Dagaror]

http://zone.ni.com/reference/en-XX/help/370051T-01/cvi/libref/cvibuild_errors_and_warnings/

[vix]

I don't understand what you mean with that link, sorry.

Could you explain it, please?

[carlox · Accepted solution]

You are wrongly using the ## operator. 

The ## operator is called also "token pasting operator" and its purpose is to tell to C preprocessor to concatenate two tokens.

You want simply to concatenate two strings: you don't need any special operator:

#define LocalDir   "E:\\"  SharedDir        // define

[vix]

Now I understand what you mean, and I tried that your suggestion works in CVI 2013

#define str1    "abcd"
#define str2    "efgh"

#define concatenated_string    str1 str2   //using a space character between the 2 strings

I don't know why ## has been working for string concatenation since CVI 6.0 to CVI 2012 SP1

I've been using it since years (I supposed that a string is a simple token, but probably it isn't)

[carlox]

Hi

Keep in mind that this is a general feature of string literals, and not something related to preprocessor directives, so you could, for example, write something like this:

printf("this "
       "is "
       "a single "
       "long "
       "string");