Windows API Reference

Home > Windows > API Reference > Kernel and User Mode > File Management

File Management Functions

This section covers the Windows API functions related to file and directory management. These functions allow applications to create, open, read, write, delete, and query information about files and directories.

Core File Operations

Directory Management

File Information and Control

CreateFile

Creates or opens a file or I/O device. It returns a handle that can be used to access the file.

HANDLE CreateFile(
  LPCTSTR               lpFileName,
  DWORD                 dwDesiredAccess,
  DWORD                 dwShareMode,
  LPSECURITY_ATTRIBUTES lpSecurityAttributes,
  DWORD                 dwCreationDisposition,
  DWORD                 dwFlagsAndAttributes,
  HANDLE                hTemplateFile
);

Parameters:

Name Type Description
lpFileName LPCTSTR The name of the file or device.
dwDesiredAccess DWORD The access to the file. Can be GENERIC_READ, GENERIC_WRITE, etc.
dwShareMode DWORD The sharing mode of the object.
lpSecurityAttributes LPSECURITY_ATTRIBUTES Security descriptor.
dwCreationDisposition DWORD Specifies how to create or open the file.
dwFlagsAndAttributes DWORD File attributes and flags.
hTemplateFile HANDLE Template file for attributes.
Important: Always check the return value for INVALID_HANDLE_VALUE and use GetLastError to retrieve error information.

ReadFile

Reads data from a file or I/O device. It fills a buffer with data read from the specified file.

BOOL ReadFile(
  HANDLE       hFile,
  LPVOID       lpBuffer,
  DWORD        nNumberOfBytesToRead,
  LPDWORD      lpNumberOfBytesRead,
  LPOVERLAPPED lpOverlapped
);

Parameters:

Name Type Description
hFile HANDLE Handle to the file to be read.
lpBuffer LPVOID Buffer that receives the data.
nNumberOfBytesToRead DWORD The maximum number of bytes to be read.
lpNumberOfBytesRead LPDWORD Number of bytes actually read.
lpOverlapped LPOVERLAPPED Overlapped structure for asynchronous operations.

WriteFile

Writes data to a file or I/O device. Writes data from a buffer into the specified file.

BOOL WriteFile(
  HANDLE       hFile,
  LPCVOID      lpBuffer,
  DWORD        nNumberOfBytesToWrite,
  LPDWORD      lpNumberOfBytesWritten,
  LPOVERLAPPED lpOverlapped
);

Parameters:

Name Type Description
hFile HANDLE Handle to the file to be written to.
lpBuffer LPCVOID Buffer containing the data to be written.
nNumberOfBytesToWrite DWORD Number of bytes to write.
lpNumberOfBytesWritten LPDWORD Number of bytes actually written.
lpOverlapped LPOVERLAPPED Overlapped structure for asynchronous operations.

DeleteFile

Deletes a specified file.

BOOL DeleteFile(
  LPCTSTR lpFileName
);

Parameters:

Name Type Description
lpFileName LPCTSTR The name of the file to be deleted.
Note: The file must not be in use and must not be read-only to be deleted successfully.

GetFileAttributes

Retrieves the attributes of a specified file or directory.

DWORD GetFileAttributes(
  LPCTSTR lpFileName
);

Parameters:

Name Type Description
lpFileName LPCTSTR The name of the file or directory.

Returns a bitmask of attribute flags (e.g., FILE_ATTRIBUTE_DIRECTORY, FILE_ATTRIBUTE_READONLY) or INVALID_FILE_ATTRIBUTES on failure.

CreateDirectory

Creates a new directory with the specified path.

BOOL CreateDirectory(
  LPCTSTR               lpPathName,
  LPSECURITY_ATTRIBUTES lpAttribute
);

Parameters:

Name Type Description
lpPathName LPCTSTR The path of the directory to create.
lpAttribute LPSECURITY_ATTRIBUTES Security descriptor.

FindFirstFile / FindNextFile

FindFirstFile searches a directory for a file or subdirectory with a name that matches a specified pattern. FindNextFile continues a directory search.

HANDLE FindFirstFile(
  LPCTSTR            lpFileName,
  LPWIN32_FIND_DATA  lpFindFileData
);

BOOL FindNextFile(
  HANDLE             hFindFile,
  LPWIN32_FIND_DATA  lpFindFileData
);

Parameters:

Name Type Description
lpFileName LPCTSTR The directory or path and file name pattern.
lpFindFileData LPWIN32_FIND_DATA Receives information about the found file or directory.
hFindFile HANDLE Handle returned by FindFirstFile.
Tip: Remember to call FindClose on the handle returned by FindFirstFile when done.

Related Topics