scope of an object and global scope

lucky6969b · 12-09-2005, 01:37 AM

I've got a var. defined as
int fd; globally available throughout my application
in a global include file say #include "myapp.h"

I've got another class which resides on another file
lets say #include "serialport.h"
this class has

serialport:

pen()
{
fd = open (....);
}

Return to the globol scope
I've got a non-class reference to fd available which always appears to be 0. Does the scope present an issue?
Thanks
Jack

dmail · 12-09-2005, 07:46 AM

so the variable is not defined as static then?
try including the following in "serialport.h" and see if that makes a difference.

Code:

extern int fd;

lucky6969b · 12-09-2005, 08:13 PM

Still zero. I actually opened the fileHandle with
#include "myapp.h"
extern int fd;
void CSerialPort::Open ()
{
fd = open(...)
}
//////////////////////////////////////////////
and access it this way
extern int fd
#include "myapp.h"
void PortMonitorThread(void)
{
read (fd..)
}

where fd is declared above all cpp files
so
in myapp.h
static int fd;

Thanks
Jack

lucky6969b · 12-09-2005, 08:14 PM

Typing mistakes. But they compiled okay

lucky6969b · 12-09-2005, 08:39 PM

The Callback function was invoked by a thread. Does it pose any problems?
Jack

lucky6969b · 12-09-2005, 08:40 PM

PortMonitorThread exactly

lucky6969b · 12-09-2005, 08:50 PM

Still zero. I actually opened the fileHandle with
#include "myapp.h"
extern int fd;
void CSerialPort::Open ()
{
fd = open(...)
}
//////////////////////////////////////////////
and access it this way
extern int fd
#include "myapp.h"
void PortMonitorThread(void)
{
read (fd..)
}

where fd is declared above all cpp files
so
in myapp.h
static int fd;

Thanks
Jack

lucky6969b · 12-09-2005, 09:09 PM

It's got to be some C versus C++ scope problems. But I don't know where to look and start. Any hints?
Thanks
Jack