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#!CNavyBlue #!N  #!Rall1141 Introduction #!N #!EC #!N #!N DXLink is 
a C programming interface that can be used to communicate with 
the Data Explorer user interface (dxui) or the Data Explorer executive 
(dxexec). Functions are provided to load programs, enable the setting and 
retrieval of named variables, control execution, handle errors, and define application-specific 
messaging. For the user interface, functions are also available to control 
window visibility and to load configuration files. For the executive, a 
function is provided to send arbitrary scripting-language commands. Support for X 
windows is built in but is not required. #!N #!N The 
kinds of application that can be written with DXLink include: #!N 
#!I0 #!N  #!F-adobe-times-medium-r-normal--18*   #!N #!N #!I30 #!N o A graphical user 
interface and demonstration utility that controls the execution of the Data 
Explorer user interface to start selected demos, flip through images, and 
remove and place windows on the display. #!N #!I30 #!N o 
A graphical user interface that communicates with the executive, replacing the 
Data Explorer user interface. #!N #!I30 #!N o A shell-like scripting 
language to control the user interface (and that might also be 
useful for a demonstration utility). #!N #!I0 #!N #!EF #!N #!N 
#!N A majority of DXLink functions have names that begin with 
the prefix "DXL." These functions can be used in communicating with 
either the user interface or the executive. The prefix "uiDXL" identifies 
a function intended for use only with the interface; the prefix 
"exDXL," a function for use only with the executive. Note: In 
the remainder of this document, references to "the server" apply to 
the user interface and the executive equally. #!N #!N All applications 
that use the DXLink facilities must link with the library libDXL.a 
and include the header file dxl.h in the source code. #!N 
#!N The functions provided by DXLink are described in more detail 
in the following sections. They have been divided into four groups: 
#!N #!I0 #!N  #!F-adobe-times-medium-r-normal--18*   #!N #!N #!I30 #!N 1.  #!Linitex,dxall1146 h Initialization and Exit  #!EL  , 
#!N #!I30 #!N 2.  #!Lmsgsys,dxall1147 h Messaging System  #!EL  ,, #!N #!I30 #!N 3.  #!Lexecctl,dxall1151 h Execution Control  #!EL  
, and #!N #!I30 #!N 4.  #!Lprgctl,dxall1152 h Program Control  #!EL  . #!N #!I0 #!N 
#!EF #!N #!N #!N The declarations for these functions are found 
in the C include file dxl.h, which should be included in 
any C file that uses them. The following sections describe three 
simple DXLink programs. All of these examples and necessary Makefiles can 
be found in /opt/local/dx/samples/dxlink. It is recommended that you create these 
programs and run them before studying the C code which follows. 
See the Readme file in /opt/local/dx/samples/dxlink for instructions on how to 
create them. #!CIndianRed #!N #!N #!N  #!F-adobe-times-bold-r-normal--18*   Stand-alone Programs #!N #!I0 
#!N  #!F-adobe-times-medium-r-normal--18*   #!N #!N #!I30 #!N 1. Stand-alone programs may access 
the Data Explorer data model by linking to the library DXlite. 
The file libDXlite.a contains a subset of Data Explorer routines (see 
 #!Ldxlap1,dxall1161 h Data Explorer Data Model Library: DXlite Routines  #!EL  ). #!N #!I30 #!N 2. Stand-alone programs may also access 
almost all Data Explorer data modules and all Data Explorer library 
routines by linking to the library libDXcallm.a. (The exceptions are such 
user-interface features as interactors, the Colormap Editor, the Image tool, and 
Get and Set.) The file libDXcallm.a contains all the Data Explorer 
library routines listed in  #!Lallr,dxall1162 h Data Explorer Library Routines  #!EL  . See also  #!Lmodacss,dxall1113 h Module Access  #!EL  . #!N 
#!I30 #!N 3. When starting Data Explorer from an external program, 
certain command line options may be useful to disable portions of 
the user interface that the external program is intended to control. 
See  #!Ldclopts7,dxall744 t Table 7  #!EL  in IBM Visualization Data Explorer User's Guide. #!N #!I0 
#!N #!EF #!N #!N #!N #!EC #!N #!N #!N  #!F-adobe-times-medium-i-normal--18*   Next 
Topic #!EF #!N #!N  #!Lall1142,dxall1143 h Example 1: sealevel.c  #!EL  #!N  #!F-adobe-times-medium-i-normal--18*   #!N 
