How can I allocate virtual memory?

[neo_in_matrix]

The following code
char* p = new char[1024 * 1024 * 512];

produces this error

terminate called after throwing an instance of 'std::bad_alloc'
what(): St9bad_alloc
Aborted

On Windows, if paging file permits, the allocation request would succeed and the kernel would return a pointer to a block of memory that is mapped in pagefile. However, you can do operations on the returned memory block just like you would physical memory.

I want to know is there any VirtualAlloc similar APIs on Linux. Thanks.

[lakerdonald]

That much memory should be malloc()'d, which returns a pointer for you anyway. (I'm assuming you're using C? I'm sure C++ has some sort of malloc() variant)

[neo_in_matrix]

Well, malloc does not throw that excetion, but it fails returning a null pointer.

[Santa's little helper]

What does ulimit give you ?

[neo_in_matrix]

ulimit gives me 'unlimited'.

However, if I try to malloc 1024 * 1024 * 128, it succeeds.

Maybe I am running out of disk space.

Here is df output:
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/VolGroup00-LogVol00
3.5G 2.4G 928M 73% /
/dev/hda1 99M 9.8M 84M 11% /boot
none 94M 0 94M 0% /dev/shm

[Giro]

Read the docs malloc returns a NULL pointer when there is no more memory left http://www.gnu.org/software/libc/man...c%20Allocation .

[jim mcnamara]

You're allocating 512 MB.

Make sure the swap file is a LOT larger than 512MB first off.

Total available memory is: (swapfile size + MB of RAM) - current usage

If the system is set up reasonably well, you should have about 2GB+ of virtual memory available. Your response may be really poor if you try it, however.

The ulimit command you want is probably

ulimit -aH