#!/usr/bin/env python
#Example 2 using NAG C libray and ctypes
#Mike Croucher - April 2008
#Concept Introduced : Callback functions

from ctypes import *
from math import *
libnag = cdll.LoadLibrary("/opt/NAG/cllux08dgl/lib/libnagc_nag.so.8")

c05adc = libnag.c05adc
c05adc.restype=None

#define python function
def py_func(x):
     return exp(-x)-x

#create the type for the c callback function
C_FUNC = CFUNCTYPE(c_double,c_double )

#now create the c callback function
c_func = C_FUNC(py_func)

a=c_double(0.0)
b=c_double(1.0)
xtol=c_double(0.00001)
ftol=c_double(0.0)
x=c_double(0.0)
fail=c_int(0)

c05adc(a, b, byref(x), c_func, xtol, ftol, fail );

print "result = %s" % (x.value)