[BAILOPAN]

Originally Posted by Drocona 1: what the hell is this stdio.h

It's "standard I/O".

Originally Posted by Drocona 2: where can i find it

Any C compiler comes with it, it's standard.

Originally Posted by Drocona 3: when i download it it comes up with 400 errors that it needs other files which i cant find anywhere

You did something wrong. Find the problem, then fix it. You shouldn't even be downloading stdio.h, it comes with any C compiler.

The other comments you make suggest that you should learn more about C++ and wait a bit until writing plugins. A quick example of how to use it:

#include <stdio.h>

void WriteFile(const char *file, const char *line)
{
    FILE *fp = fopen(file, "at");
    if (!fp)
       return;
    fprintf(fp, "%s", line);
    fclose(fp);
}

Use resources. It took me two seconds to google for "stdio.h" and find numerous resources:
http://www.cplusplus.com/ref/cstdio/
http://www.linuxgazette.com/issue24/rogers.html

If you have a specific problem, research it, then detail it and ask for help (specifically, ask "why?"). In your above example, you were mixing Valve's API with C API illegally. Filehandle_t * or whatever is something from Valve, if you read the prototype of fprintf() it requires a FILE *.