如何以快速安全的方式将十六进制字符串转换为无符号64位（uint64_t）整数？

scanf

strtoull

char *str, *end;
unsigned long long result;
errno = 0;
result = strtoull(str, &end, 16);
if (result == 0 && end == str) {
    /* str was not a number */
} else if (result == ULLONG_MAX && errno) {
    /* the value of str does not fit in unsigned long long */
} else if (*end) {
    /* str began with a number but has junk left over at the end */
}

strtoull

0x

+

-

strtoull

if (!isxdigit(str[0]) || (str[1] && !isxdigit(str[1])))

strtoull

if (str[0]=='0' && str[1])

-

strtoull("-2", 0, 16)

ULLONG_MAX-1

errno

strtoull

sscanf

const char *test = "123456789abcdef0";

errno = 0;
unsigned long long result = strtoull(test, NULL, 16);

if (errno == EINVAL)
{
    // not a valid number
}
else if (errno == ERANGE)
{
    // does not fit in an unsigned long long
}

<inttypes.h>

..._t

#include <stdio.h>
#include <inttypes.h>

sprintf( str, "%016" PRIx64, uint64 );

#include <stdio.h>
#include <inttypes.h>

sscanf( str, "%" SCNx64, &uint64 );

scanf()

scanf()