PHP Manual: Specifies the preferred record syntax for retrieval

void yaz_syntax(resource $id, string $syntax)

yaz_syntax specifies the preferred record syntax for retrieval

This function should be called before yaz_search or yaz_present.

id: The connection resource returned by yaz_connect.
syntax: The syntax must be specified as an OID (Object Identifier) in a raw dot-notation (like 1.2.840.10003.5.10) or as one of the known registered record syntaxes (sutrs, usmarc, grs1, xml, etc.).

No value is returned.