Invoke a type-specific control operation on a BIO.
Command-specific long result; often 1 for success and 0/negative for failure.
| Name | Description |
|---|---|
| bp | BIO to control. |
| cmd | BIO_CTRL_* (or type-specific) command code. |
| larg | Integer/long argument for cmd. |
| parg | Pointer argument for cmd, or NULL. |