Code for printf function in C

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> [source code of c/c++ functions](

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I was wondering where I can find the C code that's used so that when I write printf("Hello World!"); in my C programm to know that it has to print that string to STDOUT. I looked in <stdio.h>, but there I could only find its prototype int printf(const char *format, ...), but not how it looks like internally.

Here's the GNU version of `printf`... you can see it passing in `stdout` to `vfprintf`:

__printf (const char *format, ...)
{
va_list arg;
int done;

va_start (arg, format);
done = vfprintf (stdout, format, arg);
va_end (arg);

return done;
}

[See here.][1]

Here's [a link][2] to `vfprintf`... all the formatting 'magic' happens here.

The only thing that's truly 'different' about these functions is that they use varargs to get at arguments in a variable length argument list. Other than that, they're just traditional C. (This is in contrast to Pascal's `printf` equivalent, which is implemented with specific support in the compiler... at least it was back in the day.)


[1]:

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[2]:

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