#### 33.4.1 Definition of `sysconf` ¶

Function: `long int` sysconf `(int parameter)` ¶

  Preliminary: | MT-Safe env | AS-Unsafe lock heap | AC-Unsafe lock mem fd | See POSIX Safety Concepts.

  This function is used to inquire about runtime system parameters. The parameter argument should be one of the ‘`_SC_`’ symbols listed below.

  The normal return value from `sysconf` is the value you requested. A value of `-1` is returned both if the implementation does not impose a limit, and in case of an error.

  The following `errno` error conditions are defined for this function:

  `EINVAL`

    The value of the parameter is invalid.