GlPendingIO
GlPendingIO gl_pending_io(GetLine *gl)
GlPendingIO pending_io = GLP_WRITE; /* The requested information */
GlPendingIO old_pending_io = gl->pending_io;
GlPendingIO pending_io; /* The type of I/O that is currently pending */
GlPendingIO gl_pending_io(GetLine *gl);