Enum FileMode 

pub enum FileMode {
    CreateNew = 1,
    Create = 2,
    Open = 3,
    OpenOrCreate = 4,
    Truncate = 5,
    Append = 6,
}

file stream create mode

Variants

CreateNew = 1

Specifies that the operating system should create a new file. This requires System.Security.Permissions.FileIOPermissionAccess.Write permission. If the file already exists, an System.IO.IOException exception is thrown.

Create = 2

Specifies that the operating system should create a new file. If the file already exists, it will be overwritten. This requires System.Security.Permissions.FileIOPermissionAccess.Write permission. FileMode.Create is equivalent to requesting that if the file does not exist, use System.IO.FileMode.CreateNew; otherwise, use System.IO.FileMode.Truncate. If the file already exists but is a hidden file, an System.UnauthorizedAccessException exception is thrown.

Open = 3

Specifies that the operating system should open an existing file. The ability to open the file is dependent on the value specified by the System.IO.FileAccess enumeration. A System.IO.FileNotFoundException exception is thrown if the file does not exist.

OpenOrCreate = 4

Specifies that the operating system should open a file if it exists; otherwise, a new file should be created. If the file is opened with FileAccess.Read, System.Security.Permissions.FileIOPermissionAccess.Read permission is required. If the file access is FileAccess.Write, System.Security.Permissions.FileIOPermissionAccess.Write permission is required. If the file is opened with FileAccess.ReadWrite, both System.Security.Permissions.FileIOPermissionAccess.Read and System.Security.Permissions.FileIOPermissionAccess.Write permissions are required.

Truncate = 5

Specifies that the operating system should open an existing file. When the file is opened, it should be truncated so that its size is zero bytes. This requires System.Security.Permissions.FileIOPermissionAccess.Write permission. Attempts to read from a file opened with FileMode.Truncate cause an System.ArgumentException exception.

Append = 6

Opens the file if it exists and seeks to the end of the file, or creates a new file. This requires System.Security.Permissions.FileIOPermissionAccess.Append permission. FileMode.Append can be used only in conjunction with FileAccess.Write. Trying to seek to a position before the end of the file throws an System.IO.IOException exception, and any attempt to read fails and throws a System.NotSupportedException exception.

Trait Implementations

impl Debug for FileMode

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.