---
name: "PQregisterTypes"
section: "3"
platform: "linux"
package: "libpqtypes-dev"
version: "1.5.1-9"
release: "Debian 12 (Bookworm)"
platforms: ["linux"]
url: "https://new.carta.tech/PQregisterTypes"
---

# PQregisterTypes(3)

Registers sub-classes, composites and user-defined types.

## NAME

PQregisterTypes - Registers sub-classes, composites and user-defined types.

## SYNOPSIS

**#include \<libpqtypes.h\>**\
 **int PQregisterTypes(PGconn \****conn***, int** *which***, PGregisterType \****types***,**\
\
                     **int** *count***, int** *async***);**

## DESCRIPTION

*The PQregisterTypes() function allows an application* *to register one or more PQT\_SUBCLASS, PQT\_COMPOSITE or PQT\_USERDEFINED* *types which is defined by the which argument.*

*When which is PQT\_COMPOSITE or PQT\_USERDEFINED, this function must* *execute a query against the backend to retrieve type information, thus* *this should not be called from within a transaction.  It is recommended to* *register multiple composites at the same time to avoid round trip overhead.*

*The types argument is an array containing count types* *to register.  Composites do not use the typput or typget members of the* *PGregisterType structure, thus these memebrs are ignored.  If any composite* *does not exist, the register is aborted.  User-defined types must set either* *typput and/or typget for each type.   Sub-classes typname member of the* *PGregisterType structure must specify an inheritence relationship:* *ex. "myint=int4" where myint inherits from int4.  The ´=´ is called the* *inheritence operator.  If both typput and typget members of the PGregisterType* *structure are NULL, the type at that element will behave identically to the* *type it is inheriting from; an alias.  Otherwise, the base type's put and/or* *get routines will be overridden.*

*The async argument indicates if the asynchronous type registration* *should be used.  When non-zero, the caller must proceed in the normal* *async libpq fashion (PQconsumeInput, PQisBusy, PQgetResult) and provide a* *PGresult to PQregisterResult when obtained to complete the registration.*

*NOTE: The typname member of the PGregisterType structure can optionally* *contain the type's schema: schema.typname.*

*WARNING: PQparamCreate is only aware of types that have already been* *registered.  If you need to put a type into a param, make sure it is first* *registered.*

## EXAMPLES

### Using PQregisterTypes

*The example registers two composite types.*

```

```

**PGregisterType comp\_types\[\] = {**\
 	**{"myschema.simple", NULL, NULL},**\
 	**{"complex", NULL, NULL}** **};**

**if (!PQregisterTypes(conn, PQT\_COMPOSITE, comp\_types, 2, 0))**\
 	**fprintf(stderr, "PQregisterTypes: %s\\n", PQgeterror());**

## RETURN VALUE

*On success, both PQregisterTypes returns a non-zero value.* *On error, zero is returned and [PQgeterror(3)](/PQgeterror/3.md) will contain an* *error message.*

## EXAMPLES

*None.*

## AUTHOR

*A contribution of eSilo, LLC. for the PostgreSQL Database Management System.* *Written by Andrew Chernow.*

## REPORTING BUGS

*Report bugs to \<libpqtypes@esilo.com\>.*

## COPYRIGHT

*Copyright (c) 2011 eSilo, LLC. All rights reserved.*\
 *This is free software; see the source for copying conditions.* *There is NO warranty; not even for MERCHANTABILITY or  FITNESS* *FOR A PARTICULAR PURPOSE.*

## SEE ALSO

*[PQregisterResult(3)](/PQregisterResult/3.md), [pqt-handlers(3)](/pqt-handlers/3.md), [PQputf(3)](/PQputf/3.md), [PQgetf(3)](/PQgetf/3.md)*