Variable arg function question

Patrick Clochesy pcloches at
Sun May 4 14:02:50 UTC 2008

What about using a macro (...) in front of the function to csll it  
which passes __VARARGS__, NULL to ensure there is always a trailing  
NULL? I think this would at least work in GCC... Can' test on my phone  


On May 4, 2008, at 4:42 AM, Peter Boosten <peter at> wrote:

> Unga wrote:
>> Hi all
>> I need to implement a variable argument function in C.
>> The number of args are not known but the type is
>> known, all are strings.
>> Unfortunately va_arg() [stdarg(3)] does not return
>> NULL or any other suitable value after processing the
>> arg list, it just simply crashes once the arg list is
>> exhausted.
>> It seems there is no way to know the number of args
>> inside the called function.
> Why is it in your opinion so hard to count the number of arguments
> *before* you call the function, in other words, what in your program
> prevents this count?
> Peter
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