Temporary Files and Directories in Chapel

use FileSystem;
use IO;

proc check(e: Error) {
    if e {
        halt(e:string);
    }
}

proc main() {
    // The easiest way to create a temporary file is by using
    // the FileSystem module's createTempFile function. It creates
    // a file and opens it for reading and writing.
    var (tempFile, tempFilename) = createTempFile(prefix="sample");
    check(tempFile.err);

    // Display the name of the temporary file.
    writeln("Temp file name: ", tempFilename);

    // Clean up the file after we're done.
    defer {
        try! FileSystem.remove(tempFilename);
    }

    // We can write some data to the file.
    var writer = tempFile.writer();
    writer.write([1, 2, 3, 4]);
    writer.close();

    // If we intend to write many temporary files, we may
    // prefer to create a temporary directory.
    // createTempDir returns the name of the created directory.
    var tempDirname = createTempDir(prefix="sampledir");
    writeln("Temp dir name: ", tempDirname);

    defer {
        try! FileSystem.removeTree(tempDirname);
    }

    // Now we can synthesize temporary file names by
    // prefixing them with our temporary directory.
    var fname = tempDirname + "/file1";
    var f = open(fname, iomode.cw);
    var writer2 = f.writer();
    writer2.write([1, 2]);
    writer2.close();
}

This Chapel code demonstrates how to work with temporary files and directories. Here’s an explanation of the key points:

We use the FileSystem and IO modules for file operations.
The check procedure is defined to handle errors.
To create a temporary file, we use createTempFile from the FileSystem module. This function returns both the file and its name.
We use writeln to display the temporary file name.
The defer statement is used to ensure the temporary file is removed when we’re done.
We write data to the file using a writer obtained from the file.
To create a temporary directory, we use createTempDir.
We can create files within this temporary directory by concatenating the directory name with the desired file name.
The removeTree function is used to remove the temporary directory and its contents.

To run this program, save it as temp_files_and_dirs.chpl and use the Chapel compiler:

$ chpl temp_files_and_dirs.chpl
$ ./temp_files_and_dirs
Temp file name: /tmp/sample1234567890
Temp dir name: /tmp/sampledir1234567890

Note that the actual file and directory names will vary as they are generated randomly.

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Temporary Files and Directories in Chapel