How to split a string literal across multiple lines in C / Objective-C?

Question

I have a pretty long sqlite query:

const char *sql_query = "SELECT statuses.word_id FROM lang1_words, statuses WHERE statuses.word_id = lang1_words.word_id ORDER BY lang1_words.word ASC";

How can I break it in a number of lines to make it easier to read? If I do the following:

const char *sql_query = "SELECT word_id
                        FROM table1, table2
                        WHERE table2.word_id = table1.word_id
                        ORDER BY table1.word ASC";

I am getting an error.

Is there a way to write queries in multiple lines?

Answer 1

There are two ways to split strings over multiple lines:

Using \

All lines in C can be split into multiple lines using \.

Plain C:

char *my_string = "Line 1 \
                   Line 2";

Objective-C:

NSString *my_string = @"Line1 \
                        Line2";

Better approach

There's a better approach that works just for strings.

Plain C:

char *my_string = "Line 1 "
                  "Line 2";

Objective-C:

NSString *my_string = @"Line1 "
                       "Line2";    // the second @ is optional

The second approach is better, because there isn't a lot of whitespace included. For a SQL query however, both are possible.

NOTE: With a #define, you have to add an extra '\' to concatenate the two strings:

Plain C:

#define kMyString "Line 1"\
                  "Line 2"