Function nix::unistd::fpathconf

pub fn fpathconf<F: AsFd>(fd: F, var: PathconfVar) -> Result<Option<c_long>>

Like pathconf, but works with file descriptors instead of paths (see fpathconf(2))

Parameters

• fd: The file descriptor whose variable should be interrogated
• var: The pathconf variable to lookup

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