How to dynamically allocate big memory , like 10 G ,using new operator in c++ on 64-linux? -

i need dynamically allocate larger float array special application using c++ new operator, 10g. code running on 64-ubuntu-14.04 linux os 64g memory. when set request of memory 7g ,1879048192x4/(1024x1024x1024)=7g (float has 4 bytes), :

float * data;  data = new float[1879048192]; 

the program works well, when try increase request 10g , got what(): std::bad_alloc. try use malloc() take place of new operator:

data =(float*)malloc(1879048192*sizeof(float)); 

but obtain same result. ulimit -a this:

core file size          (blocks, -c) 0 data seg size           (kbytes, -d) unlimited scheduling priority             (-e) 0 file size               (blocks, -f) unlimited pending signals                 (-i) 514689 max locked memory       (kbytes, -l) 64 max memory size         (kbytes, -m) unlimited open files                      (-n) 1024 pipe size            (512 bytes, -p) 8 posix message queues     (bytes, -q) 819200 real-time priority              (-r) 0 stack size              (kbytes, -s) 8192 cpu time               (seconds, -t) unlimited max user processes              (-u) 514689 virtual memory          (kbytes, -v) unlimited file locks                      (-x) unlimited 

someone may there might no 10g continual memory allocation, close other progresses , total memory 64g. want know whether can obtain larger array or not, , how. linux limit max number dynamically allocation? , how?

i don't see problem when try it. both new , malloc worked. system runs ubuntu 15.04 , has 16g of ram.

however, if try use memory, found needed careful types of vars used index data array.

for instance, program below can undesirable things long intand float, because long int has max value of 2^31 , array length 10gi longer 2^31. also, floats add 1.0 @ time 16777216.0. doubles, ok use long int indexes here because array shorter.

use10g.c++

#include <stdio.h> #include <stdlib.h>  int main(int argc, char **argv){   long long int ten = 10;   long long int megi = 1024*1024;   long long int gigi = 1024*megi;   long long int asize = (ten*gigi)/((long int) sizeof(double));   double * data = new double[asize];   long long int i=2;   printf("a double %zd bytes\n", (size_t) sizeof(double));   printf("array size %lli \n", asize);   data[0]=0.0;   data[1]=1.0;   while (i<asize) {     data[i]=data[i-1]+1.0;     ++i;   }   printf("%lf\n", (double) data[asize-1]);   printf("success\n");   exit(exit_success); }  double 8 bytes array size 1342177280  1342177279.000000 success