Exit Error Checks

exitCheck provides a mechanism to distinguish the exit status in on.exit expressions.

exitCheck()

Details

It generates a function that is used wihtin a function's body to "flag" normal exits and in its on.exit expression to check the exit status of a function. Note that it will correctly detect errors only if all normal exit are wrapped into a call to it.

Examples

# define some function
f <- function(err){

 # initialise an error checker
  success <- exitCheck()

 # do something on exit that depends on the error status
  on.exit({
    if(success()) cat("Exit with no error: do nothing\n") 
    else cat("Exit with error: cleaning up the mess ...\n") 
  })
  
 # throw an error here
  if( err ) stop('There is an error')
 
  success(1+1)
}

# without error
f(FALSE)
#> Exit with no error: do nothing
#> [1] 2
# with error
try( f(TRUE) )
#> Exit with error: cleaning up the mess ...
#> Error in f(TRUE) : There is an error