Graceful exit

In the Perl programming language, graceful exits are generally implemented via the operator. For example, the code for opening a file often reads like the following: • Open the file 'myresults' for writing, or die with an appropriate error message. open RESULTS, '>', 'myresults' or die "can't write to 'myresults' file: $!"; If the attempt to open the file myresults fails, the containing program will terminate with an error message and an exit status indicating abnormal termination. == In Java ==

In the Java programming language, the block is used often to catch exceptions. All potentially dangerous code is placed inside the block and, if an exception occurred, is stopped, or caught. import java.io.File; import java.io.IOException; import java.util.Scanner; try { // Try to read the file "file.txt" Scanner sc = new Scanner(new File("file.txt")); while (sc.hasNextLine()) { System.out.println(sc.readLine()); } sc.close(); } catch (IOException e) { // The file could not be read System.err.println("The file could not be read. Stack trace:"); e.printStackTrace(); } == In C ==

In C one can use the error(3) function, provided in GNU by the GNU C Library. • include • include • include int fd; if ((fd = open("/dev/urandom", O_RDONLY)) If the first parameter is non-zero this function will exit from the parent process and return that parameter. == See also ==