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SystemError

SystemError(prefix::AbstractString, [errno::Int32])

A system call failed with an error code (in the errno global variable).

Examples

In the Julia programming language, the function systemerror(sysfunc, iftrue)

Raises a SystemError with the specified errno and descriptive string sysfunc if iftrue evaluates to true.

julia> systemerror("open", true)
ERROR: SystemError (with open): opening file failed
Stacktrace:
...

Common examples of its use:

1. Check if a file exists and raise an error if not:

   julia> filename = "example.txt";
   julia> if !isfile(filename)
             systemerror("open", true)
         end

   In this example, if the file "example.txt" does not exist, a SystemError is raised with the descriptive string "open".

2. Raise an error for an invalid user input:

   julia> user_input = -5;
   julia> if user_input < 0
             systemerror("input validation", true)
         end

   If the user_input is negative, a SystemError is raised with the descriptive string "input validation".

3. Handle a specific system error condition:

   julia> result = perform_operation();
   julia> if result == -1
             systemerror("system resource unavailable", true)
         end

   If the perform_operation() returns -1, indicating a specific system error condition, a SystemError is raised with the descriptive string "system resource unavailable".

Common mistake example:

julia> systemerror(5, true)
ERROR: TypeError: in systemerror, expected argument sysfunc to be a String, got Int64

In this example, the sysfunc argument is expected to be a string, but an integer is provided instead. Ensure that the sysfunc argument is of type String when using the systemerror function.

See Also

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