Handle a signal: Difference between revisions
Content added Content deleted
(Add SIGQUIT since per the task description SIGQUIT is more appropriate that SIGINT (see perl example) see discussion.) |
|||
| Line 14: | Line 14: | ||
{{omit from|XSLT}} |
{{omit from|XSLT}} |
||
Most |
Most operating systems provide interrupt facilities, sometimes called signals either generated by the user or as a result of program failure or reaching a limit like file space. |
||
Unhandled signals generally terminate a program in a disorderly manner. |
Unhandled signals generally terminate a program in a disorderly manner. |
||
Signal handlers are created so that the program behaves in a well-defined manner upon receipt of a signal. |
Signal handlers are created so that the program behaves in a well-defined manner upon receipt of a signal. |
||
;Task: |
;Task: |
||
Provide a program that displays |
Provide a program that displays an integer on each line of output at the rate of about one per half second. |
||
<!-- some systems have difficulty with 1/2 second and that's not the point of this subject anyway DG--> |
|||
Upon receipt of the |
Upon receipt of the SIGINT signal (often generated by the user typing ctrl-C <!-- on unix see stty -a . on windows SIGBREAK DG -->( or better yet, SIGQUIT ctrl-\ )) the program will cease outputting integers, output the number of seconds the program has run, and then the program will quit. <!-- outputting the number if seconds is also unduly complicated for this topic . Hope nobody minds these comments and I didn't really want to change the task since there were so many examples already written. see the Perl example for a more extensive use of signals. PS See discussion. If you find these edits inappropriate let me know DG--> |
||
<br><br> |
<br><br> |
||