Function ExtractSetVariableArgs

src/backend/utils/misc/guc.c:9208–9220

* Get the value to assign for a VariableSetStmt, or NULL if it's RESET. * The result is palloc'd. * * This is exported for use by actions such as ALTER ROLE SET. */

 * This is exported for use by actions such as ALTER ROLE SET.
 */
char *
ExtractSetVariableArgs(VariableSetStmt *stmt)
{
	switch (stmt->kind)
	{
		case VAR_SET_VALUE:
			return flatten_set_variable_args(stmt->name, stmt->args);
		case VAR_SET_CURRENT:
			return GetConfigOptionByName(stmt->name, NULL, false);
		default:
			return NULL;
	}
}

/*
 * SetPGVariable - SET command exported as an easily-C-callable function.