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:

1. Each string on its own line. Works only with strings:

   • Plain C:

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

   • Objective-C:

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

2. Using \ - can be used for any expression:

   • Plain C:

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

   • Objective-C:

     NSString *my_string = @"Line1 \                         Line2"; 

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The first 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"