Previous: Using GSL error reporting in your own functions, Up: Error Handling
Here is an example of some code which checks the return value of a function where an error might be reported,
#include <stdio.h>
#include <gsl/gsl_errno.h>
#include <gsl/gsl_fft_complex.h>
...
int status;
size_t n = 37;
gsl_set_error_handler_off();
status = gsl_fft_complex_radix2_forward (data, n);
if (status) {
if (status == GSL_EINVAL) {
fprintf (stderr, "invalid argument, n=%d\n", n);
} else {
fprintf (stderr, "failed, gsl_errno=%d\n",
status);
}
exit (-1);
}
...
The function gsl_fft_complex_radix2 only accepts integer lengths
which are a power of two. If the variable n is not a power of
two then the call to the library function will return GSL_EINVAL,
indicating that the length argument is invalid. The function call to
gsl_set_error_handler_off stops the default error handler from
aborting the program. The else clause catches any other possible
errors.