Alexis Ada Reference Manual

-- this package helps the others access the compiler static environment
-- (i.e. all the configuration files)
with system;
--with unchecked_conversion;
 
package body aada_compiler_configuration is
 
-- map the system readlink() function
function system_readlink(path: system.address; buf: system.address; bufsiz: integer)
                                                                       return integer;
pragma import(C, system_readlink, "__gnat_readlink");
 
-- overload the function so we don't have to do the C string transformation
-- every time we use it; we expect path to be the known path to the destination
-- note that if status is <= 0 then the function failed (the file is probably not
-- a symbolic link)
procedure aada_readlink(path: in string; destination: out string; status: out integer) is
  p: string(1 .. path'length + 1);
begin
  -- make the path a null terminated string
  p(1 .. path'length) := path;
  p(path'length + 1) := ascii.nul;
  status := system_readlink(path'Address, destination'address, destination'length);
end;
 
function aada_configuration_path return string is
  status: integer;
  app_path: string(1 .. 256);
begin
  -- this is currently very specific to linux
  -- see: http://stackoverflow.com/questions/1023306/finding-current-executables-path-without-proc-self-exe
  aada_readlink("/proc/self/exe", app_path, status);
  if status <= 0 then
    raise cannot_find_self_error;
  end if;
  -- status is the length of the string returned by the system readlink() function
  return app_path(1 .. status);
end aada_configuration_path;
 
 
end aada_compiler_configuration;