c - how to convert string to hexadecimal?

Question

I have a string 0xFF, is there any function like atoi which reads that string and save in a uint32_t format?

Answer 1

you can also do it with a function like this.

unsigned int foo(const char * s) {
 unsigned int result = 0;
 int c ;
 if ('0' == *s && 'x' == *(s+1)) { s+=2;
  while (*s) {
   result = result << 4;
   if (c=(*s-'0'),(c>=0 && c <=9)) result|=c;
   else if (c=(*s-'A'),(c>=0 && c <=5)) result|=(c+10);
   else if (c=(*s-'a'),(c>=0 && c <=5)) result|=(c+10);
   else break;
   ++s;
  }
 }
 return result;
}

example:

 printf("%08x
",foo("0xff"));