Matriz dinamica

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define FILAS 2
#define COLS 2
int mayor0();
void rellenar(int **,int,int);

int main(void){
signed int **matriz={0};unsigned int i=0;
/*En caso de haber error al alojar:*/
if((matriz = malloc(sizeof *matriz * FILAS)) == NULL){perror("Malloc error.Filas. \n ");exit(EXIT_FAILURE);}
for(i = 0; i < FILAS; i++){
if((matriz[i] = malloc(sizeof *matriz[i] * COLS)) == NULL){
perror("Malloc error. Columnas.\n");
exit(EXIT_FAILURE);}
return EXIT_SUCCESS;}}

void rellenar(int **matriz,int fila, int columna){
int i; max=fila*columna;
for(i=0;i<max;i++){
*(*(matriz+i))=mayor0();}}

int mayor(){
int temp=-1;
do{
setbuf(stdin,NULL);
fgets(buffer,sizeof(buffer),stdin);
buffer[strcspn(buffer,"\n")]=0;
sscanf(buffer,"%d",&temp);
}while(temp<=0);

return temp;}