This interface is specified by -p1003.1-2001. A more flexible (but non-portable) interface is provided by sysctl(3).
The confstr function provides a method for applications to get configuration defined string values. Shell programmers needing access to these parameters should use the getconf(1) utility.
The name argument specifies the system variable to be queried. Symbolic constants for each name value are found in the include file
.In unistd.h . The len argument specifies the size of the buffer referenced by the argument buf. If len is non-zero, buf is a non-null pointer, and name has a value, up to len - 1 bytes of the value are copied into the buffer buf. The copied value is always null terminated.
The available values are as follows: