A recursive function in C is a function that calls itself repeatedly until a particular condition is met. This technique provides a way to break complicated problems down into simple problems which are easier to solve. Recursive functions are very useful to solve many mathematical problems, such as calculating the factorial of a number, generating Fibonacci series, etc. .

The basic structure of recursive functions in C is as follows:

type function_name (args) {
    // function statements
    // base condition
    // recursion case (recursive call)
}

It is important to define the base condition before the recursive case, otherwise, the base condition may never be encountered and recursion might continue till the program crashes.

To prevent infinite recursion, if-else statements (or similar approach) can be used where one branch makes the recursive call, and the other doesnt.

Recursion may be a bit difficult to understand, and the developer should be very careful with recursion as it can be quite easy to slip into writing a function which never terminates, or one that uses excess amounts of memory or processor power. However, when written correctly, recursion can be a very efficient and elegant way to solve complex problems.