CreateFileW function (fileapi.h)
Creates or opens a file or I/O device. The most commonly used I/O devices are as follows: file, file stream, directory, physical disk, volume, console buffer, tape drive, communications resource, mailslot, and pipe. The function returns a handle that can be used to access the file or device for various types of I/O depending on the file or device and the flags and attributes specified.
To perform this operation as a transacted operation, which results in a handle that can be used for transacted I/O, use the CreateFileTransacted function.
Syntax
HANDLE CreateFileW(
[in] LPCWSTR lpFileName,
[in] DWORD dwDesiredAccess,
[in] DWORD dwShareMode,
[in, optional] LPSECURITY_ATTRIBUTES lpSecurityAttributes,
[in] DWORD dwCreationDisposition,
[in] DWORD dwFlagsAndAttributes,
[in, optional] HANDLE hTemplateFile
);
Parameters
[in] lpFileName
The name of the file or device to be created or opened. You may use either forward slashes (/) or backslashes (\) in this name.
For information on special device names, see Defining an MS-DOS Device Name.
To create a file stream, specify the name of the file, a colon, and then the name of the stream. For more information, see File Streams.
By default, the name is limited to MAX_PATH characters. To extend this limit to 32,767 wide characters, prepend "\\?\" to the path. For more information, see Naming Files, Paths, and Namespaces.
Tip
Starting with Windows 10, Version 1607, you can opt-in to remove the MAX_PATH limitation without prepending "\\?\". See the "Maximum Path Length Limitation" section of Naming Files, Paths, and Namespaces for details.
[in] dwDesiredAccess
The requested access to the file or device, which can be summarized as read, write, both or neither zero).
The most commonly used values are GENERIC_READ,
GENERIC_WRITE, or both
(GENERIC_READ | GENERIC_WRITE). For more information, see
Generic Access Rights,
File Security and Access Rights,
File Access Rights Constants, and
ACCESS_MASK.
If this parameter is zero, the application can query certain metadata such as file, directory, or device attributes without accessing that file or device, even if GENERIC_READ access would have been denied.
You cannot request an access mode that conflicts with the sharing mode that is specified by the dwShareMode parameter in an open request that already has an open handle.
For more information, see the Remarks section of this topic and Creating and Opening Files.
[in] dwShareMode
The requested sharing mode of the file or device, which can be read, write, both, delete, all of these, or none (refer to the following table). Access requests to attributes or extended attributes are not affected by this flag.
If this parameter is zero and CreateFile succeeds, the file or device cannot be shared and cannot be opened again until the handle to the file or device is closed. For more information, see the Remarks section.
You cannot request a sharing mode that conflicts with the access mode that is specified in an existing request that has an open handle. CreateFile would fail and the GetLastError function would return ERROR_SHARING_VIOLATION.
To enable a process to share a file or device while another process has the file or device open, use a compatible combination of one or more of the following values. For more information about valid combinations of this parameter with the dwDesiredAccess parameter, see Creating and Opening Files.
[in, optional] lpSecurityAttributes
A pointer to a SECURITY_ATTRIBUTES structure that contains two separate but related data members: an optional security descriptor, and a Boolean value that determines whether the returned handle can be inherited by child processes.
This parameter can be NULL.
If this parameter is NULL, the handle returned by CreateFile cannot be inherited by any child processes the application may create and the file or device associated with the returned handle gets a default security descriptor.
The lpSecurityDescriptor member of the structure specifies a SECURITY_DESCRIPTOR for a file or device. If this member is NULL, the file or device associated with the returned handle is assigned a default security descriptor.
CreateFile ignores the lpSecurityDescriptor member when opening an existing file or device, but continues to use the bInheritHandle member.
The bInheritHandle member of the structure specifies whether the returned handle can be inherited.
For more information, see the Remarks section.
[in] dwCreationDisposition
An action to take on a file or device that exists or does not exist.
For devices other than files, this parameter is usually set to OPEN_EXISTING.
For more information, see the Remarks section.
This parameter must be one of the following values, which cannot be combined:
[in] dwFlagsAndAttributes
The file or device attributes and flags, FILE_ATTRIBUTE_NORMAL being the most common default value for files.
This parameter can include any combination of the available file attributes (FILE_ATTRIBUTE_*). All other file attributes override FILE_ATTRIBUTE_NORMAL.
This parameter can also contain combinations of flags (FILE_FLAG_) for control of file or device caching behavior, access modes, and other special-purpose flags. These combine with any FILE_ATTRIBUTE_ values.
This parameter can also contain Security Quality of Service (SQOS) information by specifying the SECURITY_SQOS_PRESENT flag. Additional SQOS-related flags information is presented in the table following the attributes and flags tables.
For more advanced access to file attributes, see SetFileAttributes. For a complete list of all file attributes with their values and descriptions, see File Attribute Constants.
| Attribute | Meaning |
|---|---|
|
The file should be archived. Applications use this attribute to mark files for backup or removal. |
|
The file or directory is encrypted. For a file, this means that all data in the file is encrypted. For a
directory, this means that encryption is the default for newly created files and subdirectories. For more
information, see File Encryption.
This flag has no effect if FILE_ATTRIBUTE_SYSTEM is also specified. This flag is not supported on Home, Home Premium, Starter, or ARM editions of Windows. |
|
The file is hidden. Do not include it in an ordinary directory listing. |
|
The file does not have other attributes set. This attribute is valid only if used alone. |
|
The data of a file is not immediately available. This attribute indicates that file data is physically moved to offline storage. This attribute is used by Remote Storage, the hierarchical storage management software. Applications should not arbitrarily change this attribute. |
|
The file is read only. Applications can read the file, but cannot write to or delete it. |
|
The file is part of or used exclusively by an operating system. |
|
The file is being used for temporary storage.
For more information, see the Caching Behavior section of this topic. |
| Flag | Meaning |
|---|---|
|
The file is being opened or created for a backup or restore operation. The system ensures that the calling
process overrides file security checks when the process has SE_BACKUP_NAME and
SE_RESTORE_NAME privileges. For more information, see
Changing Privileges in a Token.
You must set this flag to obtain a handle to a directory. A directory handle can be passed to some functions instead of a file handle. For more information, see the Remarks section. |
|
The file is to be deleted immediately after all of its handles are closed, which includes the specified
handle and any other open or duplicated handles.
If there are existing open handles to a file, the call fails unless they were all opened with the FILE_SHARE_DELETE share mode. Subsequent open requests for the file fail, unless the FILE_SHARE_DELETE share mode is specified. |
|
The file or device is being opened with no system caching for data reads and writes. This flag does not
affect hard disk caching or memory mapped files.
There are strict requirements for successfully working with files opened with CreateFile using the FILE_FLAG_NO_BUFFERING flag, for details see File Buffering. |
|
The file data is requested, but it should continue to be located in remote storage. It should not be transported back to local storage. This flag is for use by remote storage systems. |
|
Normal reparse point processing will not
occur; CreateFile will attempt to open the reparse
point. When a file is opened, a file handle is returned, whether or not the filter that controls the reparse
point is operational.
This flag cannot be used with the CREATE_ALWAYS flag. If the file is not a reparse point, then this flag is ignored. For more information, see the Remarks section. |
|
The file or device is being opened or created for asynchronous I/O.
When subsequent I/O operations are completed on this handle, the event specified in the OVERLAPPED structure will be set to the signaled state. If this flag is specified, the file can be used for simultaneous read and write operations. If this flag is not specified, then I/O operations are serialized, even if the calls to the read and write functions specify an OVERLAPPED structure. For information about considerations when using a file handle created with this flag, see the Synchronous and Asynchronous I/O Handles section of this topic. |
|
Access will occur according to POSIX rules. This includes allowing multiple files with names, differing only in case, for file systems that support that naming. Use care when using this option, because files created with this flag may not be accessible by applications that are written for MS-DOS or 16-bit Windows. |
|
Access is intended to be random. The system can use this as a hint to optimize file caching.
This flag has no effect if the file system does not support cached I/O and FILE_FLAG_NO_BUFFERING. For more information, see the Caching Behavior section of this topic. |
|
The file or device is being opened with session awareness. If this flag is not specified, then per-session
devices (such as a device using RemoteFX USB Redirection) cannot be opened by processes running in session 0.
This flag has no effect for callers not in session 0. This flag is supported only on server editions of
Windows.
Windows Server 2008 R2 and Windows Server 2008: This flag is not supported before Windows Server 2012. |
|
Access is intended to be sequential from beginning to end. The system can use this as a hint to optimize
file caching.
This flag should not be used if read-behind (that is, reverse scans) will be used. This flag has no effect if the file system does not support cached I/O and FILE_FLAG_NO_BUFFERING. For more information, see the Caching Behavior section of this topic. |
|
Write operations will not go through any intermediate cache, they will go directly to disk.
For additional information, see the Caching Behavior section of this topic. |
The dwFlagsAndAttributes parameter can also specify SQOS information. For more information, see Impersonation Levels. When the calling application specifies the SECURITY_SQOS_PRESENT flag as part of dwFlagsAndAttributes, it can also contain one or more of the following values.
[in, optional] hTemplateFile
A valid handle to a template file with the GENERIC_READ access right. The template file supplies file attributes and extended attributes for the file that is being created.
This parameter can be NULL.
When opening an existing file, CreateFile ignores this parameter.
When opening a new encrypted file, the file inherits the discretionary access control list from its parent directory. For additional information, see File Encryption.
Return value
If the function succeeds, the return value is an open handle to the specified file, device, named pipe, or mail slot.
If the function fails, the return value is INVALID_HANDLE_VALUE. To get extended error information, call GetLastError.
Remarks
CreateFile was originally developed specifically for file interaction but has since been expanded and enhanced to include most other types of I/O devices and mechanisms available to Windows developers. This section attempts to cover the varied issues developers may experience when using CreateFile in different contexts and with different I/O types. The text attempts to use the word file only when referring specifically to data stored in an actual file on a file system. However, some uses of file may be referring more generally to an I/O object that supports file-like mechanisms. This liberal use of the term file is particularly prevalent in constant names and parameter names because of the previously mentioned historical reasons.
When an application is finished using the object handle returned by CreateFile, use the CloseHandle function to close the handle. This not only frees up system resources, but can have wider influence on things like sharing the file or device and committing data to disk. Specifics are noted within this topic as appropriate.
Windows Server 2003 and Windows XP: A sharing violation occurs if an attempt is made to open a file or directory for deletion on a remote computer when the value of the dwDesiredAccess parameter is the DELETE access flag (0x00010000) OR'ed with any other access flag, and the remote file or directory has not been opened with FILE_SHARE_DELETE. To avoid the sharing violation in this scenario, open the remote file or directory with the DELETE access right only, or call DeleteFile without first opening the file or directory for deletion.
Some file systems, such as the NTFS file system, support compression or encryption for individual files and directories. On volumes that have a mounted file system with this support, a new file inherits the compression and encryption attributes of its directory.
You cannot use CreateFile to control compression, decompression, or decryption on a file or directory. For more information, see Creating and Opening Files, File Compression and Decompression, and File Encryption.
Windows Server 2003 and Windows XP: For backward compatibility purposes, CreateFile does not apply inheritance rules when you specify a security descriptor in lpSecurityAttributes. To support inheritance, functions that later query the security descriptor of this file may heuristically determine and report that inheritance is in effect. For more information, see Automatic Propagation of Inheritable ACEs.
As stated previously, if the lpSecurityAttributes parameter is NULL, the handle returned by CreateFile cannot be inherited by any child processes your application may create. The following information regarding this parameter also applies:
- If the bInheritHandle member variable is not FALSE, which is any nonzero value, then the handle can be inherited. Therefore it is critical this structure member be properly initialized to FALSE if you do not intend the handle to be inheritable.
- The access control lists (ACL) in the default security descriptor for a file or directory are inherited from its parent directory.
- The target file system must support security on files and directories for the lpSecurityDescriptor member to have an effect on them, which can be determined by using GetVolumeInformation.
| Technology | Supported |
|---|---|
| Server Message Block (SMB) 3.0 protocol | Yes |
| SMB 3.0 Transparent Failover (TFO) | See remarks |
| SMB 3.0 with Scale-out File Shares (SO) | See remarks |
| Cluster Shared Volume File System (CsvFS) | Yes |
| Resilient File System (ReFS) | Yes |
Note that CreateFile with supersede disposition will fail if performed on a file where there is already an open alternate data stream.
Symbolic Link Behavior
If the call to this function creates a file, there is no change in behavior. Also, consider the following information regarding FILE_FLAG_OPEN_REPARSE_POINT:-
If FILE_FLAG_OPEN_REPARSE_POINT is specified:
- If an existing file is opened and it is a symbolic link, the handle returned is a handle to the symbolic link.
- If TRUNCATE_EXISTING or FILE_FLAG_DELETE_ON_CLOSE are specified, the file affected is a symbolic link.
-
If FILE_FLAG_OPEN_REPARSE_POINT is not specified:
- If an existing file is opened and it is a symbolic link, the handle returned is a handle to the target.
- If CREATE_ALWAYS, TRUNCATE_EXISTING, or FILE_FLAG_DELETE_ON_CLOSE are specified, the file affected is the target.
Caching Behavior
Several of the possible values for the dwFlagsAndAttributes parameter are used by CreateFile to control or affect how the data associated with the handle is cached by the system. They are:- FILE_FLAG_NO_BUFFERING
- FILE_FLAG_RANDOM_ACCESS
- FILE_FLAG_SEQUENTIAL_SCAN
- FILE_FLAG_WRITE_THROUGH
- FILE_ATTRIBUTE_TEMPORARY
Some of these flags should not be combined. For instance, combining FILE_FLAG_RANDOM_ACCESS with FILE_FLAG_SEQUENTIAL_SCAN is self-defeating.
Specifying the FILE_FLAG_SEQUENTIAL_SCAN flag can increase performance for applications that read large files using sequential access. Performance gains can be even more noticeable for applications that read large files mostly sequentially, but occasionally skip forward over small ranges of bytes. If an application moves the file pointer for random access, optimum caching performance most likely will not occur. However, correct operation is still guaranteed.
The flags FILE_FLAG_WRITE_THROUGH and FILE_FLAG_NO_BUFFERING are independent and may be combined.
If FILE_FLAG_WRITE_THROUGH is used but FILE_FLAG_NO_BUFFERING is not also specified, so that system caching is in effect, then the data is written to the system cache but is flushed to disk without delay.
If FILE_FLAG_WRITE_THROUGH and FILE_FLAG_NO_BUFFERING are both specified, so that system caching is not in effect, then the data is immediately flushed to disk without going through the Windows system cache. The operating system also requests a write-through of the hard disk's local hardware cache to persistent media.
A write-through request via FILE_FLAG_WRITE_THROUGH also causes NTFS to flush any metadata changes, such as a time stamp update or a rename operation, that result from processing the request. For this reason, the FILE_FLAG_WRITE_THROUGH flag is often used with the FILE_FLAG_NO_BUFFERING flag as a replacement for calling the FlushFileBuffers function after each write, which can cause unnecessary performance penalties. Using these flags together avoids those penalties. For general information about the caching of files and metadata, see File Caching.
When FILE_FLAG_NO_BUFFERING is combined with FILE_FLAG_OVERLAPPED, the flags give maximum asynchronous performance, because the I/O does not rely on the synchronous operations of the memory manager. However, some I/O operations take more time, because data is not being held in the cache. Also, the file metadata may still be cached (for example, when creating an empty file). To ensure that the metadata is flushed to disk, use the FlushFileBuffers function.
Specifying the FILE_ATTRIBUTE_TEMPORARY attribute causes file systems to avoid writing data back to mass storage if sufficient cache memory is available, because an application deletes a temporary file after a handle is closed. In that case, the system can entirely avoid writing the data. Although it does not directly control data caching in the same way as the previously mentioned flags, the FILE_ATTRIBUTE_TEMPORARY attribute does tell the system to hold as much as possible in the system cache without writing and therefore may be of concern for certain applications.
Files
If you rename or delete a file and then restore it shortly afterward, the system searches the cache for file information to restore. Cached information includes its short/long name pair and creation time.If you call CreateFile on a file that is pending deletion as a result of a previous call to DeleteFile, the function fails. The operating system delays file deletion until all handles to the file are closed. GetLastError returns ERROR_ACCESS_DENIED.
The dwDesiredAccess parameter can be zero, allowing the application to query file attributes without accessing the file if the application is running with adequate security settings. This is useful to test for the existence of a file without opening it for read and/or write access, or to obtain other statistics about the file or directory. See Obtaining and Setting File Information and GetFileInformationByHandle.
If CREATE_ALWAYS and FILE_ATTRIBUTE_NORMAL are specified, CreateFile fails and sets the last error to ERROR_ACCESS_DENIED if the file exists and has the FILE_ATTRIBUTE_HIDDEN or FILE_ATTRIBUTE_SYSTEM attribute. To avoid the error, specify the same attributes as the existing file.
When an application creates a file across a network, it is better to use
GENERIC_READ | GENERIC_WRITE for
dwDesiredAccess than to use GENERIC_WRITE alone. The
resulting code is faster, because the redirector can use the cache manager and send fewer SMBs with more data.
This combination also avoids an issue where writing to a file across a network can occasionally return
ERROR_ACCESS_DENIED.
For more information, see Creating and Opening Files.
Synchronous and Asynchronous I/O Handles
CreateFile provides for creating a file or device handle that is either synchronous or asynchronous. A synchronous handle behaves such that I/O function calls using that handle are blocked until they complete, while an asynchronous file handle makes it possible for the system to return immediately from I/O function calls, whether they completed the I/O operation or not. As stated previously, this synchronous versus asynchronous behavior is determined by specifying FILE_FLAG_OVERLAPPED within the dwFlagsAndAttributes parameter. There are several complexities and potential pitfalls when using asynchronous I/O; for more information, see Synchronous and Asynchronous I/O.File Streams
On NTFS file systems, you can use CreateFile to create separate streams within a file. For more information, see File Streams.Directories
An application cannot create a directory by using CreateFile, therefore only the OPEN_EXISTING value is valid for dwCreationDisposition for this use case. To create a directory, the application must call CreateDirectory or CreateDirectoryEx.To open a directory using CreateFile, specify the FILE_FLAG_BACKUP_SEMANTICS flag as part of dwFlagsAndAttributes. Appropriate security checks still apply when this flag is used without SE_BACKUP_NAME and SE_RESTORE_NAME privileges.
When using CreateFile to open a directory during defragmentation of a FAT or FAT32 file system volume, do not specify the MAXIMUM_ALLOWED access right. Access to the directory is denied if this is done. Specify the GENERIC_READ access right instead.
For more information, see About Directory Management.
Physical Disks and Volumes
Direct access to the disk or to a volume is restricted.Windows Server 2003 and Windows XP: Direct access to the disk or to a volume is not restricted in this manner.
You can use the CreateFile function to open a physical disk drive or a volume, which returns a direct access storage device (DASD) handle that can be used with the DeviceIoControl function. This enables you to access the disk or volume directly, for example such disk metadata as the partition table. However, this type of access also exposes the disk drive or volume to potential data loss, because an incorrect write to a disk using this mechanism could make its contents inaccessible to the operating system. To ensure data integrity, be sure to become familiar with DeviceIoControl and how other APIs behave differently with a direct access handle as opposed to a file system handle.
The following requirements must be met for such a call to succeed:
- The caller must have administrative privileges. For more information, see Running with Special Privileges.
- The dwCreationDisposition parameter must have the OPEN_EXISTING flag.
- When opening a volume or floppy disk, the dwShareMode parameter must have the FILE_SHARE_WRITE flag.
| String | Meaning |
|---|---|
| "\\.\PhysicalDrive0" | Opens the first physical drive. |
| "\\.\PhysicalDrive2" | Opens the third physical drive. |
To obtain the physical drive identifier for a volume, open a handle to the volume and call the DeviceIoControl function with IOCTL_VOLUME_GET_VOLUME_DISK_EXTENTS. This control code returns the disk number and offset for each of the volume's one or more extents; a volume can span multiple physical disks.
For an example of opening a physical drive, see Calling DeviceIoControl.
When opening a volume or removable media drive (for example, a floppy disk drive or flash memory thumb drive), the lpFileName string should be the following form: "\\.\X:". Do not use a trailing backslash (\), which indicates the root directory of a drive. The following table shows some examples of drive strings.
| String | Meaning |
|---|---|
| "\\.\A:" | Opens floppy disk drive A. |
| "\\.\C:" | Opens the C: volume. |
| "\\.\C:\" | Opens the file system of the C: volume. |
You can also open a volume by referring to its volume name. For more information, see Naming a Volume.
A volume contains one or more mounted file systems. Volume handles can be opened as noncached at the discretion of the particular file system, even when the noncached option is not specified in CreateFile. You should assume that all Microsoft file systems open volume handles as noncached. The restrictions on noncached I/O for files also apply to volumes.
A file system may or may not require buffer alignment even though the data is noncached. However, if the noncached option is specified when opening a volume, buffer alignment is enforced regardless of the file system on the volume. It is recommended on all file systems that you open volume handles as noncached, and follow the noncached I/O restrictions.
Changer Device
The IOCTL_CHANGER_* control codes for DeviceIoControl accept a handle to a changer device. To open a changer device, use a file name of the following form: "\\.\Changerx" where x is a number that indicates which device to open, starting with zero. To open changer device zero in an application that is written in C or C++, use the following file name: "\\\\.\\Changer0".Tape Drives
You can open tape drives by using a file name of the following form: "\\.\TAPEx" where x is a number that indicates which drive to open, starting with tape drive zero. To open tape drive zero in an application that is written in C or C++, use the following file name: "\\\\.\\TAPE0".For more information, see Backup.
Communications Resources
The CreateFile function can create a handle to a communications resource, such as the serial port COM1. For communications resources, the dwCreationDisposition parameter must be OPEN_EXISTING, the dwShareMode parameter must be zero (exclusive access), and the hTemplateFile parameter must be NULL. Read, write, or read/write access can be specified, and the handle can be opened for overlapped I/O.To specify a COM port number greater than 9, use the following syntax: "\.\COM10". This syntax works for all port numbers and hardware that allows COM port numbers to be specified.
For more information about communications, see Communications.
Consoles
The CreateFile function can create a handle to console input (CONIN$). If the process has an open handle to it as a result of inheritance or duplication, it can also create a handle to the active screen buffer (CONOUT$). The calling process must be attached to an inherited console or one allocated by the AllocConsole function. For console handles, set the CreateFile parameters as follows.| Parameters | Value |
|---|---|
| lpFileName |
Use the CONIN$ value to specify console input.
Use the CONOUT$ value to specify console output. CONIN$ gets a handle to the console input buffer, even if the SetStdHandle function redirects the standard input handle. To get the standard input handle, use the GetStdHandle function. CONOUT$ gets a handle to the active screen buffer, even if SetStdHandle redirects the standard output handle. To get the standard output handle, use GetStdHandle. |
| dwDesiredAccess |
GENERIC_READ | GENERIC_WRITE is preferred, but either one can
limit access.
|
| dwShareMode |
When opening CONIN$, specify
FILE_SHARE_READ. When opening CONOUT$, specify
FILE_SHARE_WRITE.
If the calling process inherits the console, or if a child process should be able to access the console,
this parameter must be |
| lpSecurityAttributes | If you want the console to be inherited, the bInheritHandle member of the SECURITY_ATTRIBUTES structure must be TRUE. |
| dwCreationDisposition | You should specify OPEN_EXISTING when using CreateFile to open the console. |
| dwFlagsAndAttributes | Ignored. |
| hTemplateFile | Ignored. |
The following table shows various settings of dwDesiredAccess and lpFileName.
| lpFileName | dwDesiredAccess | Result |
|---|---|---|
| "CON" | GENERIC_READ | Opens console for input. |
| "CON" | GENERIC_WRITE | Opens console for output. |
| "CON" | GENERIC_READ | GENERIC_WRITE |
Causes CreateFile to fail; GetLastError returns ERROR_FILE_NOT_FOUND. |
Mailslots
If CreateFile opens the client end of a mailslot, the function returns INVALID_HANDLE_VALUE if the mailslot client attempts to open a local mailslot before the mailslot server has created it with the CreateMailSlot function.For more information, see Mailslots.
Pipes
If CreateFile opens the client end of a named pipe, the function uses any instance of the named pipe that is in the listening state. The opening process can duplicate the handle as many times as required, but after it is opened, the named pipe instance cannot be opened by another client. The access that is specified when a pipe is opened must be compatible with the access that is specified in the dwOpenMode parameter of the CreateNamedPipe function.If the CreateNamedPipe function was not successfully called on the server prior to this operation, a pipe will not exist and CreateFile will fail with ERROR_FILE_NOT_FOUND.
If there is at least one active pipe instance but there are no available listener pipes on the server, which means all pipe instances are currently connected, CreateFile fails with ERROR_PIPE_BUSY.
For more information, see Pipes.
Examples
Example file operations are shown in the following topics:
- Appending One File to Another File
- Canceling Pending I/O Operations
- Creating a Child Process with Redirected Input and Output
- Creating and Using a Temporary File
- FSCTL_RECALL_FILE
- GetFinalPathNameByHandle
- Locking and Unlocking Byte Ranges in Files
- Obtaining a File Name From a File Handle
- Obtaining File System Recognition Information
- Opening a File for Reading or Writing
- Retrieving the Last-Write Time
- SetFileInformationByHandle
- Testing for the End of a File
- Using Fibers
- Using Streams
- Walking a Buffer of Change Journal Records
- Wow64DisableWow64FsRedirection
- Wow64EnableWow64FsRedirection
- Calling DeviceIoControl
- Configuring a Communications Resource
- Monitoring Communications Events
- Processing a Request to Remove a Device
Working with a mailslot is shown in Writing to a Mailslot.
A tape backup code snippet can found at Creating a Backup Application.
Note
The fileapi.h header defines CreateFile as an alias which automatically selects the ANSI or Unicode version of this function based on the definition of the UNICODE preprocessor constant. Mixing usage of the encoding-neutral alias with code that not encoding-neutral can lead to mismatches that result in compilation or runtime errors. For more information, see Conventions for Function Prototypes.
Requirements
| Requirement | Value |
|---|---|
| Minimum supported client | Windows XP [desktop apps only] |
| Minimum supported server | Windows Server 2003 [desktop apps only] |
| Target Platform | Windows |
| Header | fileapi.h (include Windows.h) |
| Library | Kernel32.lib |
| DLL | Kernel32.dll |
See also
Creating, Deleting, and Maintaining Files
Device Input and Output Control (IOCTL)
File Compression and Decompression
File Security and Access Rights
Functions
Obtaining and Setting File Information
Overview Topics