Here are a few title options based on your provided article, focusing on the question aspect: Option 1 (Direct & Concise): * Is Writing to os.Stdout in Go Concurrently Thread-Safe? Option 2 (Hi

Is Concurrent Write on Stdout Thread Safe?

Objective: Determine whether concurrent write operations on os.Stdout in Go are thread-safe.

Problem Context:

The provided code snippet in the question involves four goroutines concurrently writing to os.Stdout with varying data values. Despite the absence of data races, there is debate regarding its thread safety.

Explanation:

The fmt.*Print* functions take a value implementing the io.Writer interface and call Write on it. These functions are themselves thread-safe, allowing multiple concurrent invocations. However, the thread safety of concurrent writes depends on the underlying "writer."

Analysis:

Go's standard library wrappers for file descriptors and sockets are "thin" and delegate write operations directly to the underlying system. In the case of file descriptors like os.Stdout, POSIX requires that write(2) calls be atomic when operating on regular files or symbolic links. This implies that write operations originating from Go stdlib wrappers are thread-safe at the Go level.

Conclusion:

Based on the analysis:

• Multiple concurrent calls to fmt.Fprint* writing to the same os.Stdout are not data race-prone.
• However, the order of data written to the underlying file descriptor is unpredictable and may vary based on system factors.
• To ensure the integrity of data written to os.Stdout, consider serializing write operations using a mutex or using the log package, which employs internal locking mechanisms.

References:

• [fmt Package Documentation](https://pkg.go.dev/fmt#hdr-Printing)
• [io.Writer Interface](https://pkg.go.dev/io#Writer)
• [POSIX write(2) System Call](https://pubs.opengroup.org/onlinepubs/9699919799/functions/write.html)
• [log Package Documentation](https://pkg.go.dev/log)

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