Pike Module Reference:

Example:

   object connection = Public.Tools.FAM.Connection();

   object request = connection->monitor_file("/path/to/file");
   object event = connection->next_event();

   switch (event->code()) {
     case Public.Tools.FAM.Event.Changed: 
     case Public.Tools.FAM.Event.Deleted:  
     case Public.Tools.FAM.Event.EndExists:
       update_things();
       break;
    }
 

Monitoring ends when there are no references to the request object, so keep the request object for as long as you want to monitor.

From the FAM Manual:

Changes to files and directories are encoded in the FAMEvent structure. The code field of this structure contains one of the following enumeration constants:

Changed Some value which can be obtained with fstat(1) changed for a file or directory being monitored.

Deleted A file or directory being monitored was deleted or its name was changed. This event is also generated when monitoring starts on a nonexistent file or directory.

StartExecuting An executable file or shared library being monitored started executing. If multiple processes execute the same file, this event only occurs when the first process starts.

StopExecuting An executable file being monitored which was running finished. If multiple processes from an executable are running, this event is only generated when the last one finishes.

Created A file was created in a directory being monitored. Note: this event is only generated for files created directly in a directory being monitored; subdirectories are not automatically monitored.

Moved FAMMoved events never occur. The name remains defined so that programs that reference it will still compile.

Acknowledge After a FAMCancelMonitor, fam generates a FAMAcknowledge event. Also, if an invalid pathname is specified, fam generates a FAMAcknowledge event.

Exists When the application requests a file be monitored, fam generates a FAMExists event for that file. When the application requests a directory be monitored, fam generates a FAMExists event for that directory and every file directly contained in that directory.

EndExist When the application requests a file directory be monitored, a series of FAMExists events is generated as described above. After the last FAMExists message, fam generates a FAMEndExist message.

If a FAM event applies to a file or directory being monitored, the FAMEvent's filename field contains the full pathname that was passed to fam. If an event applies to an entry in a monitored directory, the filename field contains the relative path only. For example, if the directory /usr/tmp/xyzzy were monitored, and the file /usr/tmp/xyzzy/plugh were deleted, a FAMDeleted event would be generated containing "plugh" in filename. If the directory itself were deleted, filename would contain "/usr/tmp/xyzzy".