Error Handling Patterns

Status Code

Naming Outcomes

Small Fortran programs often return integer status values instead of throwing exceptions. A select case block can map each code to a readable outcome.

Program

Play the program to choose a status code and map it to a label.

status_code.f90 
program status_code_demo
    implicit none
    integer :: status
    character(len=12) :: label

    status = 
    select case (status)
        case (0)
            label = 'ok'
        case (1)
            label = 'retry'
        case default
            label = 'failed'
    end select
    print '(A)', trim(label)
end program status_code_demo

program status_code_demo
    implicit none
    integer :: status
    character(len=12) :: label

    status = 
    select case (status)
        case (0)
            label = 'ok'
        case (1)
            label = 'retry'
        case default
            label = 'failed'
    end select
    print '(A)', trim(label)
end program status_code_demo

program status_code_demo
    implicit none
    integer :: status
    character(len=12) :: label

    status = 
    select case (status)
        case (0)
            label = 'ok'
        case (1)
            label = 'retry'
        case default
            label = 'failed'
    end select
    print '(A)', trim(label)
end program status_code_demo
status code A small integer can summarize the result of an operation.
select case `select case` keeps outcome mapping explicit.
default case `case default` handles unexpected status values.