Izz ad-Din Ruhulessin Izz ad-Din Ruhulessin - 5 months ago 9
Python Question

Executing a C program in python?

I have this C program, at least I think it is (files: spa.c, spa.h). Is there any way I can execute this script from Python WITHOUT passing extra arguments to the Python interpreter (if not, what would the arguments be?)

Update: Thanks for your replies. The source code can be found at http://www.nrel.gov/midc/spa/#register

(Please do not be scared by the 'register' in the url, if you fill in the form, you can immediately download the files (no validation mails, etc) I will try your suggestions and report back with the results.

Update 2: I compiled the source code using gcc, but now it gives me a permission denied when trying to call(), even when running python as root (im on Ubuntu 10:10).

Update 3 [Errno 8] Exec format error

Update 4 Ok, I got it working. Program outputs values using printf:

>>> call(['/path'])
Julian Day: 2452930.312847
L: 2.401826e+01 degrees
B: -1.011219e-04 degrees
R: 0.996542 AU
H: 11.105902 degrees
Delta Psi: -3.998404e-03 degrees
Delta Epsilon: 1.666568e-03 degrees
Epsilon: 23.440465 degrees
Zenith: 50.111622 degrees
Azimuth: 194.340241 degrees
Incidence: 25.187000 degrees
Sunrise: 06:12:43 Local Time
Sunset: 17:20:19 Local Time


Thanks all!

Answer

There is no such thing as a C script. If you meant a C program you need to compile spa.c and spa.h into an executable before running it.

If you use GCC in Linux or Mac OS X:

$ gcc -Wall spa.c -o spa

Will get you an executable named spa.

After that, you can run spa program from your Python script with:

from subprocess import call
call(["./spa", "args", "to", "spa"])
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