Standard library · System and tools

os/error

The last error from a file or process operation: its code, its message and the path that failed.

import os.error

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Types
Constants and variables
Functions

When an operation in the fs.file, fs.dir, os.process or os.temp packages fails, the detail is recorded here. After any operation that can fail, ask HasError and then Last to find out what happened.

The plain functions of the os package do not record errors here; they only return a code. This package is a different thing from the general-purpose error package.

Types

`OSError`

struct OSError

The detail of an error.

Name	Type	Description
`code`	`int = 0`	The error code; one of the constants above.
`message`	`str = ""`	The error message, in English.
`operation`	`str = ""`	The name of the function that failed.
`path`	`str = ""`	The path that had the problem.
`system_code`	`int = 0`	The operating system's own error code (errno), where it is available.

os-error-Last.salam

import os.error
import fs.file

func main:
    error.Clear()
    println error.HasError()
    file.Delete("a file that does not exist.txt")
    if error.HasError():
        e := error.Last()
        println e.code == error.FileNotFound, e.operation, e.message
        println error.LastCode(), error.LastMessage()
    end
    error.Set(error.Timeout, "time ran out", "waiting", "", 0)
    println error.LastCode() == error.Timeout, error.LastMessage()
    println error.None, error.PermissionDenied, error.AlreadyExists, error.InvalidPath, error.NotSupported, error.IOError, error.ProcessFailed
end

Outputfalse true Delete delete failed 1 delete failed true time ran out 0 2 3 4 5 6 8

Constants and variables

`None`

const None: i32 = 0

No error.

The example for this item is shown with the ones above: os-error-Last.salam

`FileNotFound`

const FileNotFound: i32 = 1

The file or directory was not found.

The example for this item is shown with the ones above: os-error-Last.salam

`PermissionDenied`

const PermissionDenied: i32 = 2

Access is not allowed.

The example for this item is shown with the ones above: os-error-Last.salam

`AlreadyExists`

const AlreadyExists: i32 = 3

It is already there.

The example for this item is shown with the ones above: os-error-Last.salam

`InvalidPath`

const InvalidPath: i32 = 4

The path is not valid.

The example for this item is shown with the ones above: os-error-Last.salam

`NotSupported`

const NotSupported: i32 = 5

This system does not support the operation.

The example for this item is shown with the ones above: os-error-Last.salam

`IOError`

const IOError: i32 = 6

A read or write error.

The example for this item is shown with the ones above: os-error-Last.salam

`Timeout`

const Timeout: i32 = 7

Time ran out.

The example for this item is shown with the ones above: os-error-Last.salam

`ProcessFailed`

const ProcessFailed: i32 = 8

Running the process failed.

The example for this item is shown with the ones above: os-error-Last.salam

Functions

`Set`

func Set(code: int, message: str, operation: str, path: str, system_code: int)

Records an error, for when you are writing a package of your own and want to report through the same mechanism.

The example for this item is shown with the ones above: os-error-Last.salam

`Clear`

func Clear()

Clears the recorded error, before an operation whose error you want to check on its own.

The example for this item is shown with the ones above: os-error-Last.salam

`Last`

func Last(): OSError

The last error with all its detail.

The example for this item is shown with the ones above: os-error-Last.salam

`LastCode`

func LastCode(): int

The code of the last error.

The example for this item is shown with the ones above: os-error-Last.salam

`LastMessage`

func LastMessage(): str

The message of the last error.

The example for this item is shown with the ones above: os-error-Last.salam

`HasError`

func HasError(): bool

True when an error has been recorded.

The example for this item is shown with the ones above: os-error-Last.salam