diff --git a/numerical_methods/durand_kerner_roots.c b/numerical_methods/durand_kerner_roots.c
index fea73a03..f2839c1a 100644
--- a/numerical_methods/durand_kerner_roots.c
+++ b/numerical_methods/durand_kerner_roots.c
@@ -33,7 +33,7 @@ long double complex poly_function(double *coeffs, unsigned int degree, long doub
     return out;
 }
 
-static inline char *complex_str(long double complex x)
+const char *complex_str(long double complex x)
 {
     static char msg[50];
     double r = creal(x);