File: gawk.info,  Node: Exit Callback Functions,  Next: Extension Version String,  Prev: Extension Functions,  Up: Registration Functions

17.4.6.2 Registering An Exit Callback Function
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An "exit callback" function is a function that 'gawk' calls before it
exits.  Such functions are useful if you have general "cleanup" tasks
that should be performed in your extension (such as closing database
connections or other resource deallocations).  You can register such a
function with 'gawk' using the following function:

'void awk_atexit(void (*funcp)(void *data, int exit_status),'
'                void *arg0);'
     The parameters are:

     'funcp'
          A pointer to the function to be called before 'gawk' exits.
          The 'data' parameter will be the original value of 'arg0'.
          The 'exit_status' parameter is the exit status value that
          'gawk' intends to pass to the 'exit()' system call.

     'arg0'
          A pointer to private data that 'gawk' saves in order to pass
          to the function pointed to by 'funcp'.

   Exit callback functions are called in last-in, first-out (LIFO)
order--that is, in the reverse order in which they are registered with
'gawk'.