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copied!<p>Mixing C and Objective-C methods and function is possible, here is a simple example that uses the SQLite API within an iPhone App: (<a href="http://stanford.edu/class/cs193p/cgi-bin/index.php" rel="nofollow noreferrer">course site</a>)</p> <blockquote> <p>Download the <a href="http://stanford.edu/class/cs193p/cgi-bin/drupal/system/files/sample_code/09_MySQLiteTableView.zip" rel="nofollow noreferrer">Zip file (09_MySQLiteTableView.zip)</a></p> </blockquote> <p>C functions need to be declared outside of the <code>@implementation</code> in an Objective-C (.m) file.</p> <pre><code>int MyCFunction(int num, void *data) { //code here... } @implementation - (void)MyObjectiveCMethod:(int)number withData:(NSData *)data { //code here } @end </code></pre> <p>Because the C function is outside of the <code>@implementation</code> it cannot call methods like </p> <pre><code>[self doSomething] </code></pre> <p>and has no access to ivars.</p> <p>This can be worked around as long as the call-back function takes a <code>userInfo</code> or <code>context</code> type parameter, normally of type <code>void*</code>. This can be used to send any Objective-C object to the C function.</p> <p>As in the <a href="http://stanford.edu/class/cs193p/cgi-bin/drupal/system/files/sample_code/09_MySQLiteTableView.zip" rel="nofollow noreferrer">sample code</a>, this can be manipulated with normal Objective-C operations.</p> <p>In addition please read this answer: <a href="https://stackoverflow.com/questions/801976/mixing-c-functions-in-an-objective-c-class/802059#802059">Mixing C functions in an Objective-C class</a></p>

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