[RESOLVED] srand

[juanpast]

I'am thinking about synchronization and I begin with this code with the purpose to change it latter to insert a semaphore for example but this code not work fine... I think the trouble is with the initialization of srand...

NOTE: main function only call Inicio function.

#define NTHREADS 10
#define MAXCADENA 10

void Inicio (void);

char sCadena[MAXCADENA];

int Aleatorio(int nMin, int nMax) {	
	int nRes = nMin + rand() % ((nMax + 1) - nMin);
	return nRes;
}

void WINAPI fx(void) {	
	char c = Aleatorio(48, 90); // del 48 al 90 las letras
	int nPos = Aleatorio(0, (MAXCADENA-1));
	sCadena[nPos] = c;	
}

void Inicio (void) {

	srand(time(NULL));
	
	for(int i=0;i<NTHREADS;i++) {
		HANDLE h = CreateThread(NULL, 0, (LPTHREAD_START_ROUTINE)fx, NULL, 0, 0);	
		WaitForSingleObject(h, 100);
	}

	sCadena[MAXCADENA-1] = '\0';
	
	MessageBox(NULL, sCadena, "Cadena", MB_OK);
}

[ZuK]

I think rand() is not thread safe. You could try to use rand_s() instead.
Kurt

[juanpast]

Thanks!!