fcntl.h => close(); doesn´t exist

Hello there,

i could make it to a point to switch GPIO Pins on a B-Pi from the command line.

Primarily i want to do this from user code.
I found this
http://www.wiki.xilinx.com/GPIO+User+Space+App
telling to use fcntl.h The point is, neigther me nor my compile can find a routine "close(fd)"; I have looked in the fcntl.h directly and in
#include <sys/cdefs.h>
#include <sys/types.h>
#include <linux/fcntl.h>
which are included by the header.

Actually on first try i simply used the fopen and fprintf way, but my programm crashes then...

best regards!

http://linux.die.net/man/2/close

Close is declared in unistd.h not fcntl.h

fcntl.h should be included directly ie

#include <unistd.h>
#include <fcntl.h>

not

...
#include <linux/fcntl.h>

See:
http://linux.die.net/man/2/fcntl

hm... okay, then the problem is something else.
Looks like in my Qt Envoironment the close() method closes the App.
I need to tell the compiler that i´m refering to the close method from
unistd.h
But i´m wondering how to do that without a namespace...

Of course i´m not the first "Qt-ler" having this issue...
https://bytes.com/topic/c/answers/85...nt-unistd-h-qt
writing
::close(int)
did it

Can you not use

FILE* fd=NULL;

fd=fopen(filepath,"w");
if(fd!=NULL)
   {

...

      fclose(fd);
   }

Which opens a file at 'filepath' for writing.

I tried that, but the program crashes then. Plus the other How-To´s on this are doing it different.

But what annoys me, is that i need root level for writing to the export file. So the App needs to run as root, which is not possible by the programm itself.
Where is the sense in providing a driver but saying me i´m not allowed to use it by default...

Originally Posted by Jasson ... But what annoys me, is that i need root level for writing to the export file ...

All the stuff in /sys/* is used by the system and indiscriminate writing to it can seriously screw with your system if not completely fubar it, it is perfectly normal to need admin privileges to write to /sys/* otherwise anyone logged on could do pretty much what they want, complain to the author of the article about not making it clear that you would need root access.