SYSCONF(2,L)                AIX Technical Reference                SYSCONF(2,L)



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sysconf



PURPOSE

Retrieves the value of a system limit or option.

SYNTAX

#include <unistd.h>

long sysconf(name)
int name;

DESCRIPTION

The sysconf system call allows an application to determine the characteristics
of the system.  This function allows an application program to determine at run
time the presence of an optional facility or the value of one of the
system-wide limits.

The name parameter specifies the configuration attribute to be queried.
Symbolic values for the name parameter are defined in the file unistd.h.

Attribute     Meaning

_SC_ARG_MAX   Maximum length in bytes of arguments for the exec functions,
              including environment data.

_SC_CHILD_MAX Maximum number of simultaneous processes on this machine per real
              user ID.

_SC_CLK_TCK   The number of intervals per second, used to express the value in
              type clock_t.

_SC_NGROUPS_MAX
              Maximum number of simultaneous supplementary group IDs per
              process.

_SC_OPEN_MAX  Maximum number of files that one process can have open at any
              given time.

_SC_JOB_CONTROL
              Returns the value 0, indicating that the job control facilities
              is provided in this system.

_SC_SAVED_IDS Returns the value 0, indicating that exec functions save the
              effective user ID and effective group ID when a program starts.
              These saved IDs are then used for permission checking when being
              signalled, and when using the setuid system call.



Processed November 7, 1990       SYSCONF(2,L)                                 1

SYSCONF(2,L)                AIX Technical Reference                SYSCONF(2,L)




_SC_VERSION   Returns the currently supported version of the POSIX standard.

_SC_TCF       Returns the value 0 if the Transparent Computing Facility is
              present in this system.

_SC_NFS       Returns the value 0 if the Network File System is present in this
              system.

_SC_VECPROC_SIZE
              Returns the section size of the vector processor, if it is
              present in this system.  This parameter applies to the AIX/370
              only.

RETURN VALUE

If the sysconf system call is successful, the specified parameter is returned.
If the indicated system parameter is not set or if the specified parameter is
not limited by the system, the value -1 is returned and errno is left
unchanged.  If the name is an unrecognized value, -1 is returned and errno is
set to indicate the error.

ERROR CONDITIONS

The sysconf system call fails if the following is true:

EINVAL    The value of the name argument is invalid.

RELATED INFORMATION

In this book:  "pathconf, fpathconf."
























Processed November 7, 1990       SYSCONF(2,L)                                 2