Quickies for Unix API

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General

• Cheap profiling [permalink]
  You can use gettimeofday() to get sub-second granularity for timing:

  #include <sys/time.h>
  struct timeval start, end;
  ...
  gettimeofday (&start, NULL);
  
  ... the code you're timing
  
  gettimeofday (&end, NULL);
  double fstart, fend;
  fstart = (start.tv_sec * 1000000.0 + start.tv_usec) / 1000000.0;
  fend = (end.tv_sec * 1000000.0 + end.tv_usec) / 1000000.0;
  NSLog (@"it took %f seconds", fend - fstart);
  

• Making a timestamp with strftime [permalink]
  

      time_t now;
      now = time(NULL);
  
      struct tm *tm;
      tm = localtime (&now);
  
      char timestamp[200];
      strftime (timestamp, 200, "%m/%d/%Y-%H:%M", tm);
  

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