Large array size in C++

Walter Roberson · *nix forums Guru Joined: 19 Feb 2005 Posts: 1300

In article <1151731364.454706.270480@p79g2000cwp.googlegroups.com>,
swagat <swagat.kumar@gmail.com> wrote:

Tony 'Nicoya' Mantler · *nix forums Guru Wannabe Joined: 02 Jul 2005 Posts: 139

In article <1151731364.454706.270480@p79g2000cwp.googlegroups.com>,
"swagat" <swagat.kumar@gmail.com> wrote:

: 'ulimit -a' gives me following output on my system
: ---------------------------------------------------------------------
: $ ulimit -a
: core file size (blocks, -c) 0
: data seg size (kbytes, -d) unlimited
: file size (blocks, -f) unlimited
: max locked memory (kbytes, -l) unlimited
: max memory size (kbytes, -m) unlimited
: open files (-n) 1024
: pipe size (512 bytes, -p) 8
: stack size (kbytes, -s) 8192
: cpu time (seconds, -t) unlimited
: max user processes (-u) unlimited
: virtual memory (kbytes, -v) unlimited
: ---------------------------------------------------------------------------
:
: How do I adjust the 'ulimit' values? I read man page but it does not
: provide much information. Infact, it does not say anything about how
: to use this function.

ulimit is normally a shell builtin, so you'll want to consult the manpage for
your shell to determine how to set different values.

It would appear you're running bash (on linux, would be my guess from the values
you've pasted). I've excerpted the relevant section of the bash manpage below
for your reading convenience.

However, I don't suggest you change the ulimit values. You shouldn't be
allocating huge structures on the stack; I would suggest that the best plan is
to change your code to allocate it on the heap with malloc(3) and friends

: ulimit [-SHacdefilmnpqrstuvx [limit]]
: Provides control over the resources available to the shell and
: to processes started by it, on systems that allow such control.
: The -H and -S options specify that the hard or soft limit is set
: for the given resource. A hard limit cannot be increased once
: it is set; a soft limit may be increased up to the value of the
: hard limit. If neither -H nor -S is specified, both the soft
: and hard limits are set. The value of limit can be a number in
: the unit specified for the resource or one of the special values
: hard, soft, or unlimited, which stand for the current hard
: limit, the current soft limit, and no limit, respectively. If
: limit is omitted, the current value of the soft limit of the
: resource is printed, unless the -H option is given. When more
: than one resource is specified, the limit name and unit are
: printed before the value. Other options are interpreted as fol-
: lows:
: -a All current limits are reported
: -c The maximum size of core files created
: -d The maximum size of a process's data segment
: -e The maximum scheduling priority (`nice')
: -f The maximum size of files created by the shell
: -i The maximum number of pending signals
: -l The maximum size that may be locked into memory
: -m The maximum resident set size
: -n The maximum number of open file descriptors (most systems
: do not allow this value to be set)
: -p The pipe size in 512-byte blocks (this may not be set)
: -q The maximum number of bytes in POSIX message queues
: -r The maximum rt priority
: -s The maximum stack size
: -t The maximum amount of cpu time in seconds
: -u The maximum number of processes available to a single
: user
: -v The maximum amount of virtual memory available to the
: shell
: -x The maximum number of file locks
:
: If limit is given, it is the new value of the specified resource
: (the -a option is display only). If no option is given, then -f
: is assumed. Values are in 1024-byte increments, except for -t,
: which is in seconds, -p, which is in units of 512-byte blocks,
: and -n and -u, which are unscaled values. The return status is
: 0 unless an invalid option or argument is supplied, or an error
: occurs while setting a new limit.

Cheers - Tony 'Nicoya' Mantler :)

--
Tony 'Nicoya' Mantler - Master of Code-fu
-- nicoya@ubb.ca -- http://www.ubb.ca/ --

swagat · *nix forums beginner Joined: 30 Jun 2006 Posts: 2

Walter Roberson · *nix forums Guru Joined: 19 Feb 2005 Posts: 1300

In article <1151644162.350979.284950@h44g2000cwa.googlegroups.com>,
swagat <swagat.kumar@gmail.com> wrote:

swagat · *nix forums beginner Joined: 30 Jun 2006 Posts: 2

Hi all!

I am trying to run a Neural network program written in C++ on my SGI
prism server. But for a larger array size, it is giving me segmentation
fault.

Is there any where I can make compiler to accept higher array size?

Regards,
swagat

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