C: Correct way to print “unsigned long” in hex


I have a function that gets an <strong>unsigned long</strong> variable as parameter and I want to print it in Hex.

What is the correct way to do it?

Currently, I use <strong>printf</strong> with <strong>"%lx"</strong>

void printAddress(unsigned long address) { printf("%lx\n", address); }

Should I look for a printf pattern for <strong>unsigned</strong> long hex? (and not just "long hex" as mentioned above)

Or does <strong>printf</strong> convert numbers to hex only using the bits? - so I should not care about the sign anyway?


You're doing it right.

From <a href="http://linux.die.net/man/3/printf" rel="nofollow">the manual page</a>:


o, u, x, X

The unsigned int argument is converted to unsigned octal (o), unsigned decimal (u), or unsigned hexadecimal (x and X) notation.


So the value for x should always be unsigned. To make it long in size, use:



(ell) A following integer conversion corresponds to a long int or unsigned long int argument [...]


So %lx is unsigned long. An address (pointer value), however, should be printed with %p and cast to void *.


I think the following format specifier should work give it a try



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