Function nix::unistd::sysconf

pub fn sysconf(var: SysconfVar) -> Result<Option<c_long>>

Get configurable system variables (see sysconf(3))

Returns the value of a configurable system variable. Most supported variables also have associated compile-time constants, but POSIX allows their values to change at runtime. There are generally two types of sysconf variables: options and limits. See sysconf(3) for more details.

Returns

• Ok(Some(x)): the variable’s limit (for limit variables) or its implementation level (for option variables). Implementation levels are usually a decimal-coded date, such as 200112 for POSIX 2001.12
• Ok(None): the variable has no limit (for limit variables) or is unsupported (for option variables)
• Err(x): an error occurred