CODEWITHSUNDEEP
pythonchar
kbb
kbb

Reputation: 3415

python version of C unsigned char

I need help with a python version for this C code:

#define HostBusy_high   0x02
#define control_register    0x37a

Out32 (control_register,(unsigned char)(Inp32(control_register) | HostBusy_high));

the Out32 and Inp32 are functions located in the inpout32.dll used to interface parallel ports. These functions take hex values as their parameters. I tried to code in python to get the desired value but that is not what I am getting. See python version below:

from ctypes import windll

#parallel port instance
p_port = windll.inpout32
HostBusy_high = 0x02
control_register = 0x37a

write_data = write(p_port(Inp32(control_register) | HostBusy_high))
 Out32 (control_register,write_data))

With the code above i do not seem to get the value I want. I suspect it is the unsigned value.

Thanks

Upvotes: 1

Views: 19777

Answers (3)

jxramos
jxramos

Reputation: 8266

You can find a match in the ctypes library with the c_ubyte data type. See if you populate an object of that type with your value and find if its suitable.

https://docs.python.org/3/library/ctypes.html#ctypes.c_ubyte

The rest of the types are tabulated in https://docs.python.org/3/library/ctypes.html#fundamental-data-types

Upvotes: 0

Russell Borogove
Russell Borogove

Reputation: 19037

Depends on why you need an unsigned char. For most purposes you'll just use a Python integer. If you need to actually have a one-byte datum, you can use Python's struct.pack to make a one-byte byte string out of an integer.

You can't, in general, get good results by doing line by line literal translation of code between languages, without a good understanding of both the source and target languages, as well as the body of code you're translating.

Upvotes: 4

Hyperboreus
Hyperboreus

Reputation: 32429

Maybe you just should get the modulo 256 of your value. Then it is surely unsigned. Examples:

>>> 12 % 256
12
>>> 1022 % 256
254
>>> -1 % 256
255
>>> -127 % 256
129

Upvotes: 3

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