NAG Library Manual, Mark 27.2
```/* nag_fit_glin_linf (e02gcc) Example Program.
*
* Copyright 2021 Numerical Algorithms Group.
*
* Mark 27.2, 2021.
*/

#include <math.h>
#include <nag.h>
#include <stdio.h>

int main(void) {
/* Scalars */
double relerr, resmax, t, tol;
Integer exit_status, i, irank, iter, m, n, pda;
NagError fail;
Nag_OrderType order;

/* Arrays */
double *a = 0, *b = 0, *x = 0;

#ifdef NAG_COLUMN_MAJOR
#define A(I, J) a[(J - 1) * pda + I - 1]
order = Nag_ColMajor;
#else
#define A(I, J) a[(I - 1) * pda + J - 1]
order = Nag_RowMajor;
#endif

INIT_FAIL(fail);

exit_status = 0;
printf("nag_fit_glin_linf (e02gcc) Example Program Results\n");

/* Skip heading in data file */
scanf("%*[^\n] ");

n = 3;
scanf("%" NAG_IFMT "%*[^\n] ", &m);
if (m > 0) {
/* Allocate memory */
if (!(a = NAG_ALLOC((n + 3) * (m + 1), double)) ||
!(b = NAG_ALLOC(m, double)) || !(x = NAG_ALLOC(n, double))) {
printf("Allocation failure\n");
exit_status = -1;
goto END;
}

if (order == Nag_ColMajor)
pda = n + 3;
else
pda = m + 1;

for (i = 1; i <= m; ++i) {
scanf("%lf%lf%*[^\n] ", &t, &b[i - 1]);
A(1, i) = exp(t);
A(2, i) = exp(-t);
A(3, i) = 1.0;
}
tol = 0.0;
relerr = 0.0;
/* nag_fit_glin_linf (e02gcc).
* L_infinity-approximation by general linear function
*/
nag_fit_glin_linf(order, m, n, a, b, tol, &relerr, x, &resmax, &irank,
&iter, &fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_fit_glin_linf (e02gcc).\n%s\n", fail.message);
exit_status = 1;
goto END;
} else {
printf("\n");
printf("resmax = %11.2e  Rank = %5" NAG_IFMT "  Iterations ="
" %5" NAG_IFMT "\n",
resmax, irank, iter);

printf("\n");
printf("Solution\n");

for (i = 1; i <= n; ++i)
printf("%10.4f", x[i - 1]);
printf("\n");
}
}
END:
NAG_FREE(a);
NAG_FREE(b);
NAG_FREE(x);

return exit_status;
}
```