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(python2.1-lib.info)Resource Limits

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Resource Limits
---------------

Resources usage can be limited using the `setrlimit()' function
described below. Each resource is controlled by a pair of limits: a
soft limit and a hard limit. The soft limit is the current limit, and
may be lowered or raised by a process over time. The soft limit can
never exceed the hard limit. The hard limit can be lowered to any value
greater than the soft limit, but not raised. (Only processes with the
effective UID of the super-user can raise a hard limit.)

The specific resources that can be limited are system dependent. They
are described in the `getrlimit(2)' man page.  The resources listed
below are supported when the underlying operating system supports them;
resources which cannot be checked or controlled by the operating system
are not defined in this module for those platforms.

`getrlimit(resource)'
     Returns a tuple `(SOFT, HARD)' with the current soft and hard
     limits of RESOURCE. Raises `ValueError' if an invalid resource is
     specified, or `error' if the underyling system call fails
     unexpectedly.

`setrlimit(resource, limits)'
     Sets new limits of consumption of RESOURCE. The LIMITS argument
     must be a tuple `(SOFT, HARD)' of two integers describing the new
     limits. A value of `-1' can be used to specify the maximum
     possible upper limit.

     Raises `ValueError' if an invalid resource is specified, if the
     new soft limit exceeds the hard limit, or if a process tries to
     raise its hard limit (unless the process has an effective UID of
     super-user).  Can also raise `error' if the underyling system call
     fails.

These symbols define resources whose consumption can be controlled
using the `setrlimit()' and `getrlimit()' functions described below.
The values of these symbols are exactly the constants used by C
programs.

The UNIX man page for `getrlimit(2)' lists the available resources.
Note that not all systems use the same symbol or same value to denote
the same resource.  This module does not attempt to mask platform
differences -- symbols not defined for a platform will not be available
from this module on that platform.

`RLIMIT_CORE'
     The maximum size (in bytes) of a core file that the current process
     can create.  This may result in the creation of a partial core file
     if a larger core would be required to contain the entire process
     image.

`RLIMIT_CPU'
     The maximum amount of CPU time (in seconds) that a process can
     use. If this limit is exceeded, a `SIGXCPU' signal is sent to the
     process. (See the `signal' module documentation for information
     about how to catch this signal and do something useful, e.g. flush
     open files to disk.)

`RLIMIT_FSIZE'
     The maximum size of a file which the process may create.  This only
     affects the stack of the main thread in a multi-threaded process.

`RLIMIT_DATA'
     The maximum size (in bytes) of the process's heap.

`RLIMIT_STACK'
     The maximum size (in bytes) of the call stack for the current
     process.

`RLIMIT_RSS'
     The maximum resident set size that should be made available to the
     process.

`RLIMIT_NPROC'
     The maximum number of processes the current process may create.

`RLIMIT_NOFILE'
     The maximum number of open file descriptors for the current
     process.

`RLIMIT_OFILE'
     The BSD name for `RLIMIT_NOFILE'.

`RLIMIT_MEMLOC'
     The maximm address space which may be locked in memory.

`RLIMIT_VMEM'
     The largest area of mapped memory which the process may occupy.

`RLIMIT_AS'
     The maximum area (in bytes) of address space which may be taken by
     the process.