Function exec 

pub fn exec(
    cx: &mut Cx,
    argv: &[String],
    options: &ExecOptions,
) -> Result<ProcResult>

Runs one host process with explicit argv and bounded output.

The caller must hold exec_capability. The argv list must be non-empty; the first element is the program and the remaining elements are passed verbatim as arguments. No shell is inserted by this function.