How to display hexadecimal bytes using NSLog

Question

How can I display the following bytes using NSLog?

const void *devTokenBytes = [devToken bytes];

score 16 · Accepted Answer · edited Sep 14 '10 at 17:25

16

Assuming that devToken is of type NSData * (from the bytes call), you can use the description method on NSData to get a string containing the hexadecimal representation of the data's bytes. See the NSData class reference.

NSLog(@"bytes in hex: %@", [devToken description]);

edited Sep 14 '10 at 17:25

Chuck

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answered Sep 14 '10 at 16:50

Tim

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but now im getting the error message "warning: passing argument 1 of 'NSLog' from incompatible pointer type" – gabac Sep 14 '10 at 17:00
4

Because there's an error in the above code. He left off the @ infront of the string literal. i.e., NSLog("...") instead of NSLog(@"..."). – jer Sep 14 '10 at 17:07
jer, Chuck: thanks for pointing out and fixing, respectively. Too much C for me lately... – Tim Sep 14 '10 at 22:29
Curious, when I output the hex value, it comes wrapped with `<` and `>`. How do I get rid of that? – pixelfreak Mar 26 '13 at 22:45

score 9 · Answer 2 · edited Mar 18 '19 at 19:21

9

If you want a hex sequence:

NSMutableString *hex = [NSMutableString stringWithCapacity:[devToken length]];
for (int i=0; i < [devToken length]; i++) {
  [hex appendFormat:@"%02x", [devToken bytes][i]];
}

edited Mar 18 '19 at 19:21

evandrix

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answered May 17 '11 at 21:28

Heath Borders

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(!) `Argument type 'const void' is incomplete` – evandrix Mar 18 '19 at 19:23

How to display hexadecimal bytes using NSLog

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