Mixing C and Objective-C methods and function is possible, here is a simple example that uses the SQLite API within an iPhone App: (course site)
Download the Zip file (09_MySQLiteTableView.zip)
C functions need to be declared outside of the @implementation
in an Objective-C (.m) file.
int MyCFunction(int num, void *data)
{
//code here...
}
@implementation
- (void)MyObjectiveCMethod:(int)number withData:(NSData *)data
{
//code here
}
@end
Because the C function is outside of the @implementation
it cannot call methods like
[self doSomething]
and has no access to ivars.
This can be worked around as long as the call-back function takes a userInfo
or context
type parameter, normally of type void*
. This can be used to send any Objective-C object to the C function.
As in the sample code, this can be manipulated with normal Objective-C operations.
In addition please read this answer: Mixing C functions in an Objective-C class