yes and no.

ON EXCEPTION SET rtnsql, rtnisam, rterrmsg

rterrmsg is a char field of possibly char(80) length.

will set the reason of the error, usually the column name table name
or missing constraint name. But not the full error.

For e.g. if you are inserting a null value into a column date_of_birth
which has been declared as NOT NULL, then the above EXCEPTION will
be set as follows:-

rtnsql = -391
rtnisam = 0
rterrmsg = 'date_of_birth'

finderr -391

-391    Cannot insert a null into column column-name.

This statement tries to put a null value in the noted column. However,
that column has been defined as NOT NULL. Roll back the current
transaction. If this is a program, review the definition of the table,
and change the program logic to not use null values for columns that
cannot accept them.

No u can construct from the above that you are trying to insert null
into date_of_birth column.

In ESQL/C one can do sprintf and construct an error string which can
look like this:

Cannot insert a null into column data_of_birth which is definitely more
readable.

For me, even the SP way is good enuf to find out the cause.

However it is to be noted that if you don't have an exception block
and let the server return any error, then the server always returns full
error string as described above for ESQL/C. I don't know how the same
can be achieved using EXCEPTION block.