WriteFile

WriteFile is a commonly used function name in programming for writing data to a file or other I/O destination. While the exact signature and behavior vary by language and platform, the core purpose is to transfer a buffer of bytes from memory to a file-like object.

Windows API: In the Win32 API, the function WriteFile writes data to a file, pipe, or other I/O device identified by a file handle. The parameters include the handle, a pointer to the data buffer, the number of bytes to write, a location to store the number of bytes actually written, and an optional overlapped structure for asynchronous I/O. The function returns a success indicator, and detailed error information is obtained via system error codes.

Go language: In Go, the standard library provides a function named WriteFile (through os.WriteFile or the older ioutil.WriteFile) that writes a byte slice to a named file. It creates the file if it does not exist, and typically truncates existing content before writing, using a specified permission mode. Errors are returned for issues such as permissions, disk space, or I/O failures.

Node.js: In Node.js, the fs module offers fs.writeFile and fs.writeFileSync, which write data to a file path, creating the file if needed and replacing existing content by default. The function accepts data and encoding options, and uses a callback or throws an exception on error. It also supports asynchronous and synchronous variants.

Other languages and libraries: Many languages adopt a similarly named write function or method for file or stream I/O; some use write, writeFile, or equivalents with different defaults for encoding, append versus truncate, and error handling. The specific semantics—such as atomicity, buffering, and encoding—depend on the platform and API.

Notes: When using WriteFile, it is important to consider text versus binary data, character encoding, file permissions, and error handling. Some environments offer atomic write patterns or safety options (temporary files, flush guarantees) to prevent data corruption.