sysconf(2)                          CLIX                          sysconf(2)



  NAME

    sysconf - Retrieves configurable system variables

  LIBRARY

    Standard C Library (libc.a)

  SYNOPSIS

    #include <unistd.h>

    long sysconf(
      int name );

  PARAMETERS

    name   Specifies the system attribute to be queried.  The following table
           lists the set of system variables from <limits.h>, <unistd.h>, or
           <time.h> (for CLK_TCK) that can be returned by sysconf() and the
           symbolic constants, defined in <unistd.h> that are the
           corresponding values used for the parameter, name.

           ARG_MAX
                  (_SC_ARG_MAX)  Specifies the maximum length of arguments (in
                  bytes) for the exec() functions.

           CHILD_MAX
                  (_SC_CHILD_MAX)  Specifies the maximum number of processes
                  for each real user ID.

           CLK_TCK
                  (_SC_CLK_TCK)  Specifies the number of clock ticks per
                  second.

           NGROUPS_MAX
                  (_SC_NGROUPS_MAX)  Specifies the maximum number of
                  supplementary group IDs per process.

           OPEN_MAX
                  (_SC_OPEN_MAX)  Specifies the maximum number of files that
                  one process can have open at a time.

           _POSIX_JOB_CONTROL
                  (_SC_JOB_CONTROL)  If this symbol is defined, the
                  implementation supports job control.

           _POSIX_SAVED_IDS
                  (_SC_SAVED_IDS)  If defined, each process has a saved set-
                  user-ID and a saved set-group-ID.




  2/94 - Intergraph Corporation                                              1

  sysconf(2)                          CLIX                          sysconf(2)



           _POSIX_VERSION
                  (_SC_VERSION)  Specifies the integer value of ``1988 08L.''
                  This value changes with each published version or revision
                  of the POSIX standard to indicate the year and month that
                  the standard has approved.

           STREAM_MAX
                  (_SC_STREAM_MAX)  Specifies the maximum number of streams
                  that one process can have open at a time.

           TZNAME_MAX
                  (_SC_TZNAME_MAX)  Specifies the maximum length of a timezone
                  name.

  DESCRIPTION

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

  EXAMPLES

    To determine the maximum number of supplementary groups:

    #include <unistd.h>
    int max_groups;
    if ((max_groups = sysconf(_SC_NGROUPS_MAX)) == -1)
         perror("sysconf failed");


  RETURN VALUES

    If name is not valid, sysconf() returns -1 and sets errno to indicate the
    error.  Otherwise, sysconf() returns the current variable value on the
    system.  The value returned will not be more restrictive than the
    corresponding value described to the application when it was compiled with
    the implementations's <limits.h> or <unistd.h>.

  ERRORS

    The sysconf() function fails if the following is true:

    [EINVAL]   The value of name is not valid.

  RELATED INFORMATION

    Functions:  pathconf(2)

    Files:  limits.h(0), unistd.h(0)






  2                                              Intergraph Corporation - 2/94