| MStatus | setExistWithoutInConnections (bool flag) |
| This method specifies whether or not the node can exist without input connections. | |
| bool | existWithoutInConnections (MStatus *ReturnStatus=NULL) const |
| Determines whether or not this node can exist without input connections. | |
| MStatus | setExistWithoutOutConnections (bool flag) |
| This method specifies whether or not the node can exist without output connections. | |
| bool | existWithoutOutConnections (MStatus *ReturnStatus=NULL) const |
| Determines whether or not this node can exist without output connections. |
原文：http://www.cnblogs.com/dydx/p/4287231.html