Windows API Reference: Storage Fundamentals

This section provides an overview and detailed reference for Windows APIs related to file system operations, data storage, and management. Understanding these APIs is crucial for developing applications that interact with the file system, manage data persistence, and ensure data integrity.

The Windows operating system provides a rich set of APIs that allow applications to access and manipulate files, directories, streams, and other storage-related objects. These APIs cover a wide range of functionalities, from basic file creation and deletion to advanced features like file locking, asynchronous I/O, and managing disk quotas.

Key Concepts in Windows Storage

File System Objects: Understanding the difference between files, directories, symbolic links, and other file system entities.
File I/O Operations: Reading, writing, seeking, and truncating files.
Asynchronous I/O: Performing I/O operations without blocking the application thread, improving responsiveness.
File Metadata: Accessing and modifying file attributes such as timestamps, permissions, and ownership.
Volume Management: Working with disk volumes, partitions, and file system formats.
Stream Operations: Utilizing alternate data streams for storing metadata or additional file content.

Core Storage APIs

The following table lists some of the most commonly used Win32 APIs for storage operations:

API Function	Description	Related Topics
`CreateFile`	Creates or opens a file, directory, disk, or pipe.	File Handles, File Access Rights
`ReadFile`	Reads data from a file or communication device.	Asynchronous I/O
`WriteFile`	Writes data to a file or communication device.	Asynchronous I/O
`SetFilePointer`	Moves the file pointer for the specified file.	File Positioning
`CloseHandle`	Closes an open object handle.	File Handles
`GetFileAttributes`	Retrieves the attributes of a specified file or directory.	File Attributes
`CreateDirectory`	Creates a new directory.	Directory Management
`DeleteDirectory`	Deletes an existing directory.	Directory Management

Example: Reading from a File

This example demonstrates how to open a file, read its contents into a buffer, and then display the contents.


#include <windows.h>
#include <stdio.h>

int main() {
    HANDLE hFile;
    char buffer[256];
    DWORD bytesRead;
    BOOL bRead;

    // Open the file for reading
    hFile = CreateFile(
        L"example.txt",             // File name
        GENERIC_READ,               // Desired access
        FILE_SHARE_READ,            // Share mode
        NULL,                       // Security attributes
        OPEN_EXISTING,              // Creation disposition
        FILE_ATTRIBUTE_NORMAL,      // Flags & attributes
        NULL);                      // Template file

    if (hFile == INVALID_HANDLE_VALUE) {
        printf("Error opening file: %lu\n", GetLastError());
        return 1;
    }

    // Read from the file
    bRead = ReadFile(
        hFile,          // Handle to the file
        buffer,         // Destination buffer
        255,            // Number of bytes to read
        &bytesRead,     // Number of bytes read
        NULL);          // Overlapped structure

    if (bRead) {
        buffer[bytesRead] = '\0'; // Null-terminate the string
        printf("File content:\n%s\n", buffer);
    } else {
        printf("Error reading file: %lu\n", GetLastError());
    }

    // Close the file handle
    CloseHandle(hFile);

    return 0;
}

MSDN Documentation

Storage Fundamentals

Key Concepts in Windows Storage

Core Storage APIs

Example: Reading from a File

Further Reading