11-06-2008
Question about the system() function in C
Hello all !
Could someone throw some light on whether there's a limit to the number of characters contained in the command string that is passed to the system() call in C.
Is it OS dependent? If yes, what are the limits for each?
Thanks.
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LEARN ABOUT ULTRIX
prlimit
PRLIMIT(1) User Commands PRLIMIT(1)
NAME
prlimit - get and set process resource limits
SYNOPSIS
prlimit [options] [--resource[=limits] [--pid PID]
prlimit [options] [--resource[=limits] command [argument...]
DESCRIPTION
Given a process ID and one or more resources, prlimit tries to retrieve and/or modify the limits.
When command is given, prlimit will run this command with the given arguments.
The limits parameter is composed of a soft and a hard value, separated by a colon (:), in order to modify the existing values. If no lim-
its are given, prlimit will display the current values. If one of the values is not given, then the existing one will be used. To specify
the unlimited or infinity limit (RLIM_INFINITY), the -1 or 'unlimited' string can be passed.
Because of the nature of limits, the soft limit must be lower or equal to the high limit (also called the ceiling). To see all available
resource limits, refer to the RESOURCE OPTIONS section.
soft:hard Specify both limits.
soft: Specify only the soft limit.
:hard Specify only the hard limit.
value Specify both limits to the same value.
GENERAL OPTIONS
-h, --help
Display help text and exit.
--noheadings
Do not print a header line.
-o, --output list
Define the output columns to use. If no output arrangement is specified, then a default set is used. Use --help to get a list of
all supported columns.
-p, --pid
Specify the process id; if none is given, the running process will be used.
--raw Use the raw output format.
--verbose
Verbose mode.
-V, --version
Display version information and exit.
RESOURCE OPTIONS
-c, --core[=limits]
Maximum size of a core file.
-d, --data[=limits]
Maximum data size.
-e, --nice[=limits]
Maximum nice priority allowed to raise.
-f, --fsize[=limits]
Maximum file size.
-i, --sigpending[=limits]
Maximum number of pending signals.
-l, --memlock[=limits]
Maximum locked-in-memory address space.
-m, --rss[=limits]
Maximum Resident Set Size (RSS).
-n, --nofile[=limits]
Maximum number of open files.
-q, --msgqueue[=limits]
Maximum number of bytes in POSIX message queues.
-r, --rtprio[=limits]
Maximum real-time priority.
-s, --stack[=limits]
Maximum size of the stack.
-t, --cpu[=limits]
CPU time, in seconds.
-u, --nproc[=limits]
Maximum number of processes.
-v, --as[=limits]
Address space limit.
-x, --locks[=limits]
Maximum number of file locks held.
-y, --rttime[=limits]
Timeout for real-time tasks.
EXAMPLES
prlimit --pid 13134
Display limit values for all current resources.
prlimit --pid 13134 --rss --nofile=1024:4095
Display the limits of the RSS, and set the soft and hard limits for the number of open files to 1024 and 4095, respectively.
prlimit --pid 13134 --nproc=512:
Modify only the soft limit for the number of processes.
prlimit --pid $$ --nproc=unlimited
Set for the current process both the soft and ceiling values for the number of processes to unlimited.
prlimit --cpu=10 sort -u hugefile
Set both the soft and hard CPU time limit to ten seconds and run 'sort'.
SEE ALSO
ulimit(1), prlimit(2)
NOTES
The prlimit system call is supported since Linux 2.6.36, older kernels will break this program.
AUTHORS
Davidlohr Bueso <dave@gnu.org> - In memory of Dennis M. Ritchie.
AVAILABILITY
The prlimit command is part of the util-linux package and is available from https://www.kernel.org/pub/linux/utils/util-linux/.
util-linux July 2014 PRLIMIT(1)