Page History

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Code Block

bgColor	#FFCCCC
lang	c

enum {len = 12};
char id[len];  /* id will hold the ID, starting with
                * the characters "ID" followed by a
                * random integer */
int r;
int num;
/* ... */
r = rand();  /* generateGenerate a random integer */
num = snprintf(id, len, "ID%-d", r);  /* generateGenerate the ID */
/* ... */

Compliant Solution (POSIX)

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Code Block

bgColor	#ccccff
lang	c

enum {len = 12};
char id[len];  /* id will hold the ID, starting with
                * the characters "ID" followed by a
                * random integer */
int r;
int num;
/* ... */
time_t now = time(NULL);
if (now == (time_t) -1) {
  /* handle error */
}
srandom(now);  /* seedSeed the PRNG with the current time */
/* ... */
r = random();  /* generateGenerate a random integer */
num = snprintf(id, len, "ID%-d", r);  /* generateGenerate the ID */
/* ... */

The rand48 family of functions provides another alternative for pseudorandom numbers.

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To achieve the best random numbers possible, an implementation-specific function must be used. When unpredictability really matters and speed is not an issue, as in the creation of strong cryptographic keys, use a true entropy source, such as /dev/random, or a hardware device capable of generating random numbers. Note that the /dev/random device can block for a long time if there are not enough events going on to generate sufficient entropy.

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LDRA tool suiteLDRALDRA V.

Tool

Version

Checker

Description

Compass/ROSE

ECLAIR