Reading DLLs in Python

$ # On linux 64 bit system, Build and run the sample c program:
$ ./a.out 

Gaseous attenuation = 0.11 dB

Gaseous attenuation exceeded for 0.01 % of the time = 0.14 dB

Clouds attenuation exceeded for 0.01 % of the time = 0.22 dB

Scintillation impairment exceeded for 0.01 % of the time = 0.43 dB

Rain attenuation exceeded for 0.01 % of the time = 6.00 dB

import math
import propa

TAU = 2*math.pi                         # http://www.youtube.com/watch?v=jG7vhMMXagQ

lat = 46.217                            # Latitude (°)
lon = 6.12                              # Logitude (°)

hs = 0.8140                             # Earth station altitude (km)
E = 33.0*TAU/360                        # Link elevation angle (°)

f = 12.0                                # Link frequency (GHz)
to = 45.0                               # Tilt polarization angle (°)

D = 1.0                           # Earth station antenna diameter (m)
eta = 0.5			# Earth station antenna efficiency
import propa

p = 0.01                                # Percentage of the time

# Intermediate parameters computation
hr = propa.rain_height(lat,lon)
R001 = propa.rain_intensity(lat,lon,0.01)
Temp = propa.temperature(lat,lon)
ro = propa.SWVD(lat,lon)
WVC = propa.IWVC(lat,lon,p)
LWC = propa.LWCC(lat,lon,p)
Nwet = propa.NWET(lat,lon)

# GASEOUS ATTENUATION
Agaseous = propa.gaseous_attenuation(f,E,Temp,ro)
print("\nGaseous attenuation = %.2f dB"%Agaseous)

# GASEOUS ATTENUATION EXCEEDED FOR p% OF THE TIME
Agaseous = propa.gaseous_attenuation_exc(f,E,Temp,WVC,ro)
print("\nGaseous attenuation exceeded for %.2f %% of the time = %.2f dB"%(p,Agaseous))

# CLOUD ATTENUATION EXCEEDED FOR p% OF THE TIME
Aclouds = propa.cloud_attenuation(f,E,LWC)
print("\nClouds attenuation exceeded for %.2f %% of the time = %.2f dB"%(p,Aclouds))

# IMPAIRMENT DUE TO SCINTILLATION EXCEEDED FOR p% OF THE TIME
Iscint = propa.scintillation(Nwet,f,E,p,hs,eta,D)
print("\nScintillation impairment exceeded for %.2f %% of the time = %.2f dB"%(p,Iscint))

# RAIN ATTENUATION EXCEEDED FOR p% OF THE TIME
Arain = propa.rain_attenuation(lat,f,E,p,hs,hr,R001,to)
print("\nRain attenuation exceeded for %.2f %% of the time = %.2f dB"%(p,Arain))

# http://docs.python.org/py3k/library/ctypes.html

import ctypes
D = ctypes.c_double

# You probably want this instead of windll.LoadLibrary
propa = ctypes.WinDLL(r"D:\Windows\SysWOW64\propa.dll") # use a raw string, otherwise your backslashes may be lost.

def dress(library,attribute,return_type,argument_types):
    function = getattr(library,attribute)
    function.argtypes = argument_types
    function.restype = return_type
    return function

NWET = dress(propa,'NWET',D,(D,D,)) # extern double NWET(double lat, double lon);
rain_height = dress(propa,'rain_height',D,(D,D,)) # extern double rain_height(double lat, double lon);

# fill in the rest
#extern double temperature(double lat,double lon);
#extern double rain_intensity(double lat, double lon, double p);
#extern double rain_probability(double lat, double lon);
#extern double LWCC(double lat, double lon, double p);
#extern double IWVC(double lat, double lon, double p) ;
#extern double SWVD(double lat, double lon);
#extern double gaseous_attenuation(double f,double E,double Temp, double ro);
#extern double gaseous_attenuation_exc(double f,double E,double Temp, double WVC, double ro);
#extern double cloud_attenuation(double f,double E,double L);
#extern double rain_attenuation(double lat,double f,double E,double p,double hs,double hr,double R001, double to);
#extern double scintillation(double Nwet, double f,double E,double p,double hs,double eta, double D);

#
#>>> import ctypes
#>>> math = ctypes.CDLL(ctypes.util.find_library('m'))
#>>> math
#<CDLL 'libm.so.6', handle 7fc1831c94d8 at 165aa50>
#>>> math.hypot
#<_FuncPtr object at 0x15fd600>
#>>> D = ctypes.c_double
#>>> hypot = math.hypot
#>>> hypot.argtypes = (D,D,)
#>>> hypot.restype = D
#>>> hypot(3,4)
#5.0