NAME

XOpenDisplay, XCloseDisplay - connect or disconnect to X server

SYNTAX

Display *XOpenDisplay(char *_d_i_s_p_l_a_y___n_a_m_e); int XCloseDisplay(Display *_d_i_s_p_l_a_y);

ARGUMENTS

_d_i_s_p_l_a_y Specifies the connection to the X server.
_d_i_s_p_l_a_y___n_a_m_e Specifies the hardware display name, which determines the display
and communications domain to be used. On a POSIX-conformant system, if the display_name is NULL, it defaults to the value of the DISPLAY environment variable.

DESCRIPTION

The _X_O_p_e_n_D_i_s_p_l_a_y function returns a _D_i_s_p_l_a_y structure that serves as the connection to the X server and that contains all the information about that X server. _X_O_p_e_n_D_i_s_p_l_a_y connects your application to the X server through TCP or DECnet communications protocols, or through some local inter-process communication protocol. If the hostname is a host machine name and a single colon (:) separates the hostname and display number, _X_O_p_e_n_D_i_s_p_l_a_y connects using TCP streams. If the hostname is not specified, Xlib uses whatever it believes is the fastest transport. If the hostname is a host machine name and a double colon (::) separates the hostname and display number, _X_O_p_e_n_D_i_s_p_l_a_y connects using DECnet. A single X server can support any or all of these transport mechanisms simultaneously. A particular Xlib implementation can support many more of these transport mechanisms.

If successful, _X_O_p_e_n_D_i_s_p_l_a_y returns a pointer to a _D_i_s_p_l_a_y structure, which is defined in <_X_1_1_/_X_l_i_b_._h>. If _X_O_p_e_n_D_i_s_p_l_a_y does not succeed, it returns NULL. After a successful call to _X_O_p_e_n_D_i_s_p_l_a_y, all of the screens in the display can be used by the client. The screen number specified in the display_name argument is returned by the _D_e_f_a_u_l_t_S_c_r_e_e_n macro (or the _X_D_e_f_a_u_l_t_S_c_r_e_e_n function). You can access elements of the _D_i_s_p_l_a_y and _S_c_r_e_e_n structures only by using the information macros or functions. For information about using macros and functions to obtain information from the _D_i_s_p_l_a_y structure, see section 2.2.1.

The _X_C_l_o_s_e_D_i_s_p_l_a_y function closes the connection to the X server for the display specified in the _D_i_s_p_l_a_y structure and destroys all windows, resource IDs (_W_i_n_d_o_w, _F_o_n_t, _P_i_x_m_a_p, _C_o_l_o_r_m_a_p, _C_u_r_s_o_r, and _G_C_o_n_t_e_x_t), or other resources that the client has created on this display, unless the close-down mode of the resource has been changed (see _X_S_e_t_C_l_o_s_e_D_o_w_n_M_o_d_e). Therefore, these windows, resource IDs, and other resources should never be referenced again or an error will be generated. Before exiting, you should call _X_C_l_o_s_e_D_i_s_p_l_a_y explicitly so that any pending errors are reported as _X_C_l_o_s_e_D_i_s_p_l_a_y performs a final _X_S_y_n_c operation.

_X_C_l_o_s_e_D_i_s_p_l_a_y can generate a _B_a_d_G_C error.

SEE ALSO

AllPlanes(3X11), XFlush(3X11), XSetCloseDownMode(3X11)
_X_l_i_b _- _C _L_a_n_g_u_a_g_e _X _I_n_t_e_r_f_a_c_e