sysconf(3POSIX)

NAME | SYNOPSIS | DESCRIPTION | RETURN VALUES | ERRORS | ATTRIBUTES

NAME

sysconf- get configurable system variables

SYNOPSIS

#include <posix/unistd.h>

long sysconf(int name);

DESCRIPTION

The sysconf() function provides a method for the application to determine the current value of a configurable system limit or option (variable).

The name argument represents the system variable to be queried. The symbolic constants used for name are defined in <posix/unistd.h> and appear in the right-hand column of the table that follows.

Some of the variables in the left-hand column of the following table are independent of the system configuration and are also defined in <limits.h> or <posix/unistd.h> if the _POSIX_MRTP_SOURCE feature test macro is defined before these headers are included.

 

Variable	Name Value
ARG_MAX	_SC_ARG_MAX
DELAYTIMER_MAX	_SC_DELAYTIMER_MAX
_MQ_OPEN_MAX	_SC_MQ_OPEN_MAX
_MQ_PRIO_MAX	_SC_MQ_PRIO_MAX
_MQ_DFL_MSGSIZE	_SC_MQ_DFL_MSGSIZE
_MQ_DFL_MAXMSGNB	_SC_MQ_DFL_MAXMSGNB
_MQ_PATHMAX	_SC_MQ_PATHMAX
NGROUPS_MAX	_SC_NGROUPS_MAX
OPEN_MAX	_SC_OPEN_MAX
PAGESIZE	_SC_PAGESIZE
PTHREAD_DESTRUCTOR_ITERATIONS	_SC_PTHREAD_DESTRUCTOR_ITERATIONS
PTHREAD_KEYS_MAX	_SC_PTHREAD_KEYS_MAX
PTHREAD_STACK_MIN	_SC_PTHREAD_STACK_MIN
PTHREAD_THREADS_MAX	_SC_PTHREAD_THREADS_MAX
SEM_VALUE_MAX	_SC_SEM_VALUE_MAX
SHM_PATHMAX	_SC_SHM_PATHMAX
TIMER_MAX	_SC_TIMER_MAX
TZNAME_MAX	_SC_TZNAME_MAX
_POSIX_MESSAGE_PASSING	_SC_MESSAGE_PASSING
_POSIX_SEMAPHORES	_SC_SEMAPHORES
_POSIX_SHARED_MEMORY_OBJECTS	_SC_SHARED_MEMORY_OBJECTS
_POSIX_THREADS	_SC_THREADS
_POSIX_THREAD_ATTR_STACKADDR	_SC_THREAD_ATTR_STACKADDR
_POSIX_THREAD_ATTR_STACKSIZE	_SC_THREAD_ATTR_STACKSIZE
_POSIX_THREAD_PRIORITY_SCHEDULING	_SC_THREAD_PRIORITY_SCHEDULING
_POSIX_THREAD_PRIO_INHERIT	_SC_THREAD_PRIO_INHERIT
_POSIX_THREAD_PRIO_PROTECT	_SC_THREAD_PRIO_PROTECT
_POSIX_THREAD_PROCESS_SHARED	_SC_THREAD_PROCESS_SHARED
_POSIX_THREAD_SAFE_FUNCTIONS	_SC_THREAD_SAFE_FUNCTIONS
_POSIX_TIMERS	_SC_TIMERS
_POSIX_VERSION	_SC_VERSION

RETURN VALUES

If name is an invalid value, sysconf() returns -1. If the variable corresponding to name is associated with a functionality that is not supported by the system, sysconf() returns -1 without changing the value of errno.

Otherwise, sysconf() returns the current value of the variable on the system. The value returned is no more restrictive than the corresponding value passed to the application when it was compiled with <limits.h> or <posix/unistd.h>. The value does not change during the lifetime of the calling actor.

ERRORS

[EINVAL]

The name argument is invalid.

ATTRIBUTES

See attributes(5) for descriptions of the following attributes:

ATTRIBUTE TYPE	ATTRIBUTE VALUE
Interface Stability	Evolving

NAME | SYNOPSIS | DESCRIPTION | RETURN VALUES | ERRORS | ATTRIBUTES