8. Application Guidelines

• 8.1.1. Symbolic Defines
• 8.1.2. Header Files
• 8.1.3. Aborting and Terminating the Application
  

8.1. General Guidelines

This chapter offers advice and suggestions for programmers designing and coding Dialogic ISDN applications in a Windows or a LINUX environment. Specific guidelines for developing ISDN applications are provided.

Topics include the following:

• general guidelines
• handling events, errors and alarms
• programming considerations
• diagnostic tools

NOTE:

These guidelines are not intended as a comprehensive guide to developing or debugging Dialogic ISDN applications.

This section provides general guidelines for writing applications including explanations of:

• symbolic defines
• header files
• aborting and terminating the application

8.1.1. Symbolic Defines

Applications containing numerical values for defines are subject to obsolescence. In general, Dialogic recommends using symbolic defined names rather than numerical values. Defines are found in the cclib.h header file.

8.1.2. Header Files

Various header files must be included in an ISDN application. These files provide the equates, structures, and prototypes needed to compile application programs. The following header files are typically used for ISDN call control applications:

• cclib.h - ISDN Call Control library defines
• isdncmd.h - ISDN command structure defines
• isdnlib.h - ISDN library headers
• isdnerr.h - ISDN error defines
• srllib.h - SRL headers for event handling
• dtilib.h - DTI headers for layer 1 board device handling

8.1.3. Aborting and Terminating the Application

Upon aborting a Dialogic ISDN API application, the operating system terminates the current process, but may leave devices in an unknown state. This may result in errors the next time the application is run. To avoid errors of this type, the application should trap the following terminating signals to terminate the application:

1. Disconnect all active calls (in CONNECTED state).
2. Abort all calls in progress, either by dropping and releasing the call or by issuing cc_Restart( ) on each line device.
3. Set the line state to "Out of Service" or "Maintenance" if that option is available in the protocol being used.

When the process completes, any device claimed with cc_Open( ) must be released using the cc_Close( ) function.

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