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Parus Khan Posted
5-Sep-2002 21:30 GMT Toolset
C166 |  Sending Binary Data with "printf" Parus Khan Hi..
I want to send Binary Data using printf() function
for examle if I do printf("%d",i) where i=16706 then printf() function transmit that integer in text mode (not in Binary mode) i.e. it will send 5 bytes for 16706.
If I use %X instead of %d even then it will send 4142 in HEX....that means 4 bytes.
Now if somhow I can send the number 16706 in binary .... it will become 0xAB which is only two bytes .
so for any integer upto 65636.... I can send it as binary in only two bytes..
I f somone knows...pls let me know.
Thanks....
| | Read-Only Author
Jon Ward Posted
5-Sep-2002 21:43 GMT Toolset
C166 | RE: Sending Binary Data with "printf" Jon Ward
putchar(number);
putchar(number>>8);
or
putchar(number>>8);
putchar(number);
Jon | | Read-Only Author
Parus Khan Posted
5-Sep-2002 22:45 GMT Toolset
C166 | RE: Sending Binary Data with "printf" Parus Khan Thanks Jhon.....It works..
But how can we send Binary Data when we have a float data type instead of integer. | | Read-Only Author
Andrew Neil Posted
5-Sep-2002 23:25 GMT Toolset
C166 | RE: Sending Binary Data with "printf" Andrew Neil "But how can we send Binary Data when we have a float data type instead of integer."
You will have to read the compiler Manual to find the internal representation of the float type, and then devise a means to access the individual bytes of that representation.
This is standard 'C' stuff; the main choices are:
[1] shift & mask - usually portable, but often slow;
[2] use a union - non-portable, but usually quicker
Try a 'Search', as this has definitely been discussed before! | | Read-Only Author
Jon Ward Posted
5-Sep-2002 23:39 GMT Toolset
C166 | RE: Sending Binary Data with "printf" Jon Ward how can we send Binary Data when we have a float data type
.
.
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float x;
putchar (((unsigned char *) &x) [0]);
putchar (((unsigned char *) &x) [1]);
putchar (((unsigned char *) &x) [2]);
putchar (((unsigned char *) &x) [3]);
.
.
.
Jon | | Read-Only Author
Andrew Neil Posted
5-Sep-2002 23:35 GMT Toolset
C166 | RE: Sending Binary Data with "printf" Andrew Neil "printf() function transmit that integer in text mode (not in Binary mode) i.e. it will send 5 bytes for 16706"
Well of course it does!
The clue is in the function name: printf - clearly this is aimed at a printing output device, which will naturally expect text output!
This should also serve as a warning to you: it is up to you to ensure that your entire communications link can pass binary data; it only takes one step in the link to interpret your binary data as control codes, and the entire link will get messed up.
Be careful! | |
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