XSetState, XSetFunction, XSetPlaneMask, XSetForeground, XSetBackground - GC
  convenience routines
int XSetState(Display *display, GC gc, unsigned
    long foreground, unsigned long background, int
    function, unsigned long plane_mask);
int XSetFunction(Display *display, GC gc, int
    function);
int XSetPlaneMask(Display *display, GC gc,
    unsigned long plane_mask);
int XSetForeground(Display *display, GC gc,
    unsigned long foreground);
int XSetBackground(Display *display, GC gc,
    unsigned long background);
  - background
- Specifies the background you want to set for the specified GC.
- display
- Specifies the connection to the X server.
- foreground
- Specifies the foreground you want to set for the specified GC.
- function
- Specifies the function you want to set for the specified GC.
- gc
- Specifies the GC.
- plane_mask
- Specifies the plane mask.
The XSetState function sets the foreground, background, plane mask, and
  function components for the specified GC.XSetState can generate BadAlloc, BadGC, and
    BadValue errors.
XSetFunction sets a specified value in the specified
  GC.
XSetFunction can generate BadAlloc, BadGC,
    and BadValue errors.
The XSetPlaneMask function sets the plane mask in the
    specified GC.
XSetPlaneMask can generate BadAlloc and BadGC
    errors.
The XSetForeground function sets the foreground in the
    specified GC.
XSetForeground can generate BadAlloc and
    BadGC errors.
The XSetBackground function sets the background in the
    specified GC.
XSetBackground can generate BadAlloc and
    BadGC errors.
  - BadAlloc
- The server failed to allocate the requested resource or server
    memory.
- BadGC
- A value for a GContext argument does not name a defined GContext.
- BadValue
- Some numeric value falls outside the range of values accepted by the
      request. Unless a specific range is specified for an argument, the full
      range defined by the argument's type is accepted. Any argument defined as
      a set of alternatives can generate this error.
XCreateGC(3), XQueryBestSize(3), XSetArcMode(3), XSetClipOrigin(3),
  XSetFillStyle(3), XSetFont(3), XSetLineAttributes(3), XSetTile(3)
Xlib - C Language X Interface