NAME

XConnectionNumber, ConnectionNumber — get connection number or file descriptor. 

SYNOPSIS

int XConnectionNumber(display)
      Display ∗display;

ARGUMENTS

displaySpecifies a connection to an X server; returned from XOpenDisplay(). 

RETURNS

The connection number. 

DESCRIPTION

XConnectionNumber() returns the connection number for the specified display.  On a POSIX-conformant system, this is the file descriptor of the connection. 

The C language macro ConnectionNumber() is equivalent and slightly more efficient. 

Xlib Reference Manual