read out MAC-Adresse + hex to string, string to hex

[Guest_imported]

Hello
I have two questions.
1. How can I read out a MAC-Address from a Network Interface card?
2. I read a hexadecimal figure from a file into an Array of char(String). I want to increment
the hex- figure. Afterwards I have to write the hexadecimal figure into a file.
My question: How can I convert a String into a hexadecimal figure and the other way around?
Thank you for your help

 

[rbobbitt]

As to the 1st question, this is quite operating system dependent, so nobody can reasonably help you without more details about your environment. Furthermore, it's not really a C question, so you might have better luck asking in a forum dedicated to your system.

For the 2nd question, use strtol() or strtoul() to convert the string representation of the hex number to decimal:

#include <stdio.h>
#include <stdlib.h>

/* ... */

char hex[]=&quot;0x1bcd34&quot;;
char buf[100]; /* arbitrary limit of 100 */

unsigned num=(unsigned)strtol(hex,NULL,16);

/* use sprintf() to convert it back */

sprintf(buf,&quot;%X&quot;,&num);

HTH,

Russ
bobbitts@hotmail.com

http://home.earthlink.net/~bobbitts