The following code works, but when I change my size larger than 10 I get segmentation faults. I'm pretty sure it has to do with the pointer somehow I just can't figure it out!

I need to make my matrix larger, by setting the matrix[SIZE][SIZE] to size 10000.

#define SIZE 100

It only works whenamatrix[SIZE][SIZE] to size 100.

#define SIZE 10

Any help will be greatly appreciated! Thanks!

Endomlic

Code://I had to change the size to 10 from 100 because //of segmentation faults #include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <sys/wait.h> #include <sys/shm.h> #include <sys/ipc.h> #include <sys/types.h> #define SIZE 10 <---------------------------HERE struct matrix { int C[SIZE][SIZE]; }*c_ptr; int A[SIZE][SIZE], B[SIZE][SIZE]; void randomize(int dim, int); void compute_element(int, int); void print(); int main(int argc, char * argv[]) { int shmid, status; int i,j,l,m,z, children = 1; pid_t pid; shmid = shmget((key_t)1234, sizeof(int) * SIZE * SIZE, 0666 | IPC_CREAT); c_ptr = shmat(shmid, 0, 0); // place random values in A and B randomize(SIZE,10000); //Spawns chlidren based on user parameter //default is 1 if(!(argc < 2)) { children = atoi(argv[1]); } printf("%d process(es) spawned. To spawn more processes type number after program name.\n", children); pid = fork(); if(pid == 0){ for( l = 0; l < (SIZE/2); l++ ){ for( m = 0; m < (SIZE/2); m++ ) { for(z = 0; z < children; z++){ pid = fork(); if(pid == 0){ (void) shmat(shmid, 0, 0); compute_element(l,m); //exit child _exit(status); } } } } //exit child _exit(status); } //the other half the parent will handle for( i = (SIZE/2); i < SIZE; i++ ){ for( j = (SIZE/2); j < SIZE; j++ ) { (void) shmat(shmid, 0, 0); compute_element(i,j); } } //wait for child to exit before printing wait(&status); print(); return 0; } void randomize(int dim, int big) { int i,j; for( i = 0; i < dim; i++ ) for( j = 0; j < dim; j++ ) { A[i][j] = random() % big; B[i][j] = random() % big; } } void compute_element(int iNum, int jNum) { int k; { c_ptr->C[iNum][jNum] = 0; for( k = 0; k < SIZE; k++ ) if( (k % 2) == 0 ) c_ptr->C[iNum][jNum] += A[iNum][k] * A[k][jNum]; else c_ptr->C[iNum][jNum] -= A[iNum][k] * A[k][jNum]; } } void print() { int i; for(i = 0; i < SIZE; i++) { int row = random() % SIZE; int col = random() % SIZE; printf("C[%d][%d] = %d\n", row, col, c_ptr->C[row][col]); } }