hi, Till:
Complex is a struct data type in nag, while complex is built-in data type in Origin C, please update to code like the following:
#include <Origin.h>
#include <OC_nag8.h>
#include <NAG\OC_nag_ex.h>
#include <NAG\nagx04.h>
#include <NAG\nag_stdlib.h>
#include <NAG\nagf04.h>
void test()
{
complex a[4], b[2], x[2];
int i;
NagError fail;
a[0].m_re= 1;
a[0].m_im= 0;
a[1].m_re= 1;
a[1].m_im= 2;
a[2].m_re= 1;
a[2].m_im= 1;
a[3].m_re= 0;
a[3].m_im= 3;
b[0].m_re= 1;
b[0].m_im= 0;
b[1].m_re= 0;
b[1].m_im= 0;
printf("Solution\n");
for (i = 0; i < 4; i++)
printf("(%7.4f, %7.4f)\n", a[i].m_re, a[i].m_im);
printf("Solution\n");
for (i = 0; i < 2; i++)
printf("(%7.4f, %7.4f)\n", b[i].m_re, b[i].m_im);
nag_complex_lin_eqn_mult_rhs(2, 1, a, 2, b, 1, x, 1, &fail);
return;
}