In a Pro*C file, I have a very straightforward anonymous PL/SQL block like this:

EXEC SQL EXECUTE
DECLARE
    nrows pls_integer := 0;
BEGIN
    select count(*) into nrows from tbl;

    if nrows != 1 then
        RAISE_APPLICATION_ERROR(-20000,
                    'The table must contain exactly one row');
    else
        select stuff into :stuff FROM tbl;
    end if;
END; 
END-EXEC;

Pro*C protests with:

CSF-S-00201, identifier 'RAISE_APPLICATION_ERROR' must be declared

However, moving the anonymous PL/SQL block to the SQL developer (and adding a stuff variable):

DECLARE
    nrows pls_integer := 0;
    stuff NUMBER := 0;
BEGIN
    select count(*) into nrows from tbl;

    if nrows != 1 then
        RAISE_APPLICATION_ERROR(-20000,
                    'The table must contain exactly one row');
    else
        select stuff into :stuff FROM tbl;
    end if;
END;
/

works fine. What could be going on? The schema I’m using to compile the Pro*C file and to execute the block in SQL developer is the same.