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Once again, take srand()/random() out of the initialization chain.

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They have exactly the wrong kind of randomness for this job - not
returning consistent sequences across different platforms or C library
versions, and because pseodorandom not really better than sampling
the clock.
This commit is contained in:
Eric S. Raymond 2017-05-24 23:36:25 -04:00
parent 6146406990
commit 6ba9a7de7f
3 changed files with 6 additions and 7 deletions
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2
main.c
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@ -99,7 +99,7 @@ int main(int argc, char *argv[]) {
lcgstate.a = 1093; lcgstate.a = 1093;
lcgstate.c = 221587; lcgstate.c = 221587;
lcgstate.m = 1048576; lcgstate.m = 1048576;
set_seed_from_time(); set_seed((long)time(NULL));
/* Read the database if we have not yet done so */ /* Read the database if we have not yet done so */

9
misc.c
View file

@ -724,7 +724,8 @@ L2: ATDWRF=I;
/* Utility routines (SETBIT, TSTBIT, set_seed_from_time, get_next_lcg_value, randrange, RNDVOC, BUG) */ /* Utility routines (SETBIT, TSTBIT, set_seed, get_next_lcg_value,
* randrange, RNDVOC, BUG) */
#undef SETBIT #undef SETBIT
long fSETBIT(long BIT) { long fSETBIT(long BIT) {
@ -759,11 +760,9 @@ long TSTBIT;
#define TSTBIT(MASK,BIT) fTSTBIT(MASK,BIT) #define TSTBIT(MASK,BIT) fTSTBIT(MASK,BIT)
void set_seed_from_time(void) void set_seed(long seedval)
{ {
/* Use the current system time to get seed the ISO rand() function, from which we get a seed for the LCG. */ lcgstate.x = (unsigned long) seedval % lcgstate.m;
srand(time(NULL));
lcgstate.x = (unsigned long) rand() % lcgstate.m;
} }
unsigned long get_next_lcg_value(void) unsigned long get_next_lcg_value(void)

2
misc.h
View file

@ -73,6 +73,6 @@ extern long fIABS(long);
#define IABS(N) fIABS(N) #define IABS(N) fIABS(N)
extern long fMOD(long,long); extern long fMOD(long,long);
#define MOD(N,M) fMOD(N,M) #define MOD(N,M) fMOD(N,M)
extern void set_seed_from_time(void); extern void set_seed(long);
extern unsigned long get_next_lcg_value(void); extern unsigned long get_next_lcg_value(void);
extern long randrange(long); extern long randrange(long);