duplicating printf()

I need to write a function that has the same parameters as printf(),
eg. my_printf(char*, ...), that will perform some minor operations
and then call the printf() function. What is the correct way to define
my function so that I can then pass the parameters to printf()?

Put another way, what is the type of the variable argument list,
"...", in the example below??


Thanks

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int my_printf(char* pfmt,...)
{
// misc code here
printf(pfmt,...);
}

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