Question

I downloaded, compiled, and installed the GNU Scientific Library (gsl) on my mac, which locates /usr/local/include/gsl as default.

To test it, I have tried to compile and execute the example C program (found from gsl document).

 #include <stdio.h>
 #include <gsl/gsl_statistics.h>

 int
 main(void)
 {
   double data[5] = {17.2, 18.1, 16.5, 18.3, 12.6};
   double mean, variance, largest, smallest;

   mean     = gsl_stats_mean(data, 1, 5);
   variance = gsl_stats_variance(data, 1, 5);
   largest  = gsl_stats_max(data, 1, 5);
   smallest = gsl_stats_min(data, 1, 5);

   printf ("The dataset is %g, %g, %g, %g, %g\n",
          data[0], data[1], data[2], data[3], data[4]);

   printf ("The sample mean is %g\n", mean);
   printf ("The estimated variance is %g\n", variance);
   printf ("The largest value is %g\n", largest);
   printf ("The smallest value is %g\n", smallest);
   return 0;
 }

To compile it,

$ gcc -I /usr/local/include -c example.c

$ ls

example.c example.o

And, to execute it,

$ ./example.o

-bash: ./example.o: Permission denied

What’s happening? Who can run it other than me?

Answer 1

example.o is an object file, not an executable.

According to the documentation (info gsl-ref to read it), this should work (or at least it’s close).

$ gcc -Wall -I/usr/local/include -c example.c
$ gcc -L/usr/local/lib example.o -lgsl -lgslcblas -lm -o example
$ ./example