parameters

The view information_schema.parameters contains information about all input arguments of functions and procedures and output result columns of functions in the database.
Use condition is_result = 'NO' to retrieve only the input arguments.
Use condition is_result = 'YES' to retrieve only the output result columns.
Note that table producing functions can have more than one output result column.
Note that MonetDB supports function and procedure overloading (same name but with different arguments). Use the specific_name instead of function_name to distinguish them.

SELECT * FROM information_schema.parameters;
SELECT * FROM information_schema.parameters WHERE is_result = 'NO';
SELECT * FROM information_schema.parameters WHERE is_result = 'YES';
SELECT specific_schema, function_name, specific_name, is_result, ordinal_position, parameter_mode, parameter_name, data_type
 FROM information_schema.parameters WHERE NOT is_system;

information_schema.parameters

column nametyperemarks
specific_catalogVARCHARAlways NULL
specific_schemaVARCHAR
specific_nameVARCHARCurrently consists of function_name and function_id between ( and )
ordinal_positionINTEGER
parameter_modeVARCHARIN or OUT
is_resultVARCHARNO or YES
as_locatorVARCHARAlways NULL
parameter_nameVARCHAR
from_sql_specific_catalogVARCHARAlways NULL
from_sql_specific_schemaVARCHARAlways NULL
from_sql_specific_nameVARCHARAlways NULL
to_sql_specific_catalogVARCHARAlways NULL
to_sql_specific_schemaVARCHARAlways NULL
to_sql_specific_nameVARCHARAlways NULL
data_typeVARCHAR
character_maximum_lengthINTEGER
character_octet_lengthBIGINT
character_set_catalogVARCHARAlways NULL
character_set_schemaVARCHARAlways NULL
character_set_nameVARCHAR
collation_catalogVARCHARAlways NULL
collation_schemaVARCHARAlways NULL
collation_nameVARCHARAlways NULL
numeric_precisionINTEGER
numeric_precision_radixINTEGER
numeric_scaleINTEGER
datetime_precisionINTEGER
interval_typeVARCHAR
interval_precisionINTEGER
udt_catalogVARCHARAlways NULL
udt_schemaVARCHARAlways NULL
udt_nameVARCHARAlways NULL
scope_catalogVARCHARAlways NULL
scope_schemaVARCHARAlways NULL
scope_nameVARCHARAlways NULL
maximum_cardinalityINTEGERAlways NULL
dtd_identifierVARCHARAlways NULL
declared_data_typeVARCHARAlways NULL
declared_numeric_precisionINTEGERAlways NULL
declared_numeric_scaleINTEGERAlways NULL
parameter_defaultVARCHARAlways NULL
schema_idINTEGERreference to sys.schemas.id
function_idINTEGERreference to sys.functions.id
arg_idINTEGERreference to sys.args.id
function_nameVARCHARalso known as routine_name
function_typeINTEGERreference to sys.function_types.function_type_id
is_systemBOOLEANtrue when it is a parameter of a system function or procedure, else false

Note: The last 6 columns (schema_id, function_id, arg_id, function_name, function_type and is_system) are extensions to the view as defined by ISO standard. They provide useful information and simplify filtering and joins with system tables/views in sys schema when needed.