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One of my characters are short named Orius and its pronounced "oh rye us" and like my friends always pronounce it as "oor ee us"

Chronophobic

0

37

11

12

April 28, 2015 16:30:12

One of my characters are short named Orius and its pronounced "oh rye us" and like my friends always pronounce it as "oor ee us"

(Hmm, from 3 weeks ago. I don't copy much)

it seems like most answers never actually tried to run your code. here's a very minimalistic program, that indeed exhibits your problem:

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

int main() {
int seed = time(NULL);
struct random_data *qq = NULL;

qq = calloc(1, sizeof(struct random_data));
if(qq) {
srandom_r(seed, qq); /* segfault! */
} else {
printf("failed to allocate `qq`\n");
}
return 0;
}

valgrind doesn't show much apart from an illegal memory access:

==22907== Invalid write of size 4 ==22907== at 0x409CE8D: srandom_r (random_r.c:182) ==22907== by 0x80484A1: main (srand_ko.c:10) ==22907== Address 0x0 is not stack'd, malloc'd or (recently) free'd

now when looking at the random_data struct, you will find that it contains a pointer to a state-buffer:

struct random_data
{
int32_t *fptr; /* Front pointer. */
int32_t *rptr; /* Rear pointer. */
int32_t *state; /* Array of state values. */
int rand_type; /* Type of random number generator. */
int rand_deg; /* Degree of random number generator. */
int rand_sep; /* Distance between front and rear. */
int32_t *end_ptr; /* Pointer behind state table. */
};

obviously all those pointers will be NULL if you allocate with calloc(), and srandom_r doesn't really like that. you can help it be manually allocating an array of state values and assign it to the random_data struct using initstate_r. since initstate_r already takes a seed, you don't need to call srandom_r anymore (but you can if you want to):

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

#define STATESIZE 64
int main() {
int seed = time(NULL);
char*buf = (char*)calloc(STATESIZE, sizeof(char));
struct random_data *qq = NULL;

qq = calloc(1, sizeof(struct random_data));
initstate_r(seed, buf, STATESIZE, qq);
/* generate some random numbers */
/* ... */

srandom_r(seed, qq);
/* generate the same random numbers again */

Atholis

0

69

106

35

April 28, 2015 16:31:59

(Hmm, from 3 weeks ago. I don't copy much)

it seems like most answers never actually tried to run your code. here's a very minimalistic program, that indeed exhibits your problem:

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

int main() {
int seed = time(NULL);
struct random_data *qq = NULL;

qq = calloc(1, sizeof(struct random_data));
if(qq) {
srandom_r(seed, qq); /* segfault! */
} else {
printf("failed to allocate `qq`\n");
}
return 0;
}

valgrind doesn't show much apart from an illegal memory access:

==22907== Invalid write of size 4 ==22907== at 0x409CE8D: srandom_r (random_r.c:182) ==22907== by 0x80484A1: main (srand_ko.c:10) ==22907== Address 0x0 is not stack'd, malloc'd or (recently) free'd

now when looking at the random_data struct, you will find that it contains a pointer to a state-buffer:

struct random_data
{
int32_t *fptr; /* Front pointer. */
int32_t *rptr; /* Rear pointer. */
int32_t *state; /* Array of state values. */
int rand_type; /* Type of random number generator. */
int rand_deg; /* Degree of random number generator. */
int rand_sep; /* Distance between front and rear. */
int32_t *end_ptr; /* Pointer behind state table. */
};

obviously all those pointers will be NULL if you allocate with calloc(), and srandom_r doesn't really like that. you can help it be manually allocating an array of state values and assign it to the random_data struct using initstate_r. since initstate_r already takes a seed, you don't need to call srandom_r anymore (but you can if you want to):

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

#define STATESIZE 64
int main() {
int seed = time(NULL);
char*buf = (char*)calloc(STATESIZE, sizeof(char));
struct random_data *qq = NULL;

qq = calloc(1, sizeof(struct random_data));
initstate_r(seed, buf, STATESIZE, qq);
/* generate some random numbers */
/* ... */

srandom_r(seed, qq);
/* generate the same random numbers again */

Ath's Arcane Spiral Master Clan

Last edited on Apr 28, 2015 16:32:27 by Atholis

http://www.dreamhorse.com/ad/1939789.html

((I've been horse shopping so the only thing I've been copying is links to sales ads XD))

Tzarksra

94

44

225

1426

April 28, 2015 16:39:23

http://www.dreamhorse.com/ad/1939789.html

((I've been horse shopping so the only thing I've been copying is links to sales ads XD))

Kit | she/them
FR +2
coatl connossieur

yes helo this is my sitting device keep your nasty walking sticks out from under it

sagestuck

0

59

206

2288

April 28, 2015 16:46:02

yes helo this is my sitting device keep your nasty walking sticks out from under it

[url=http://flightrising.com/main.php?dragon=12420128] [img]http://flightrising.com/rendern/350/124202/12420128_350.png[/img] [/url] i play a lot of forum games...