w_ioctl(), __w_pioctl() — Control of devices

#define _OPEN_SYS
#include <termios.h>

int w_ioctl(int fildes, int cmd, int arglen, void *arg);
int __w_pioctl(const char *pathname, int cmd, int arglen, void *arg);

ACL format:

#define _OPEN_SYS
#include <termios.h>
#include <sys>

int w_ioctl(int fildes, int cmd, int arglen, void arg);
int __w_pioctl(const char pathname, int cmd, int arglen, void arg);

The w_ioctl() and __w_pioctl() functions are general entry points for device-specific commands. The specific actions specified by w_ioctl() and __w_pioctl() vary with the device, and they are defined by the device driver.

fildes

A descriptor for an open character special file (used by w_ioctl).

pathname

The pathname of a file (used by __w_pioctl).

cmd

The command to be passed to the device driver as an integer value.

Command

Description

SIOCGPARTNERINFO

Provides an interface for an application to retrieve security information about its partner. For more information, see z/OS Communications Server: IP Programmer's Guide and Reference.

arglen

The length of the argument passed to the device driver.

arg

The address of the buffer where the argument to be passed to the device driver is stored.

If unsuccessful, w_ioctl() returns -1 and sets errno to one of the following values:

Error Code

Description

EACCES

Permission is denied.

EINVAL

One of the following situations occurred:

• An incorrect length was specified for arglen. The correct argument length range is 0 to 50,000.
• An invalid message queue was specified when command _IOCC_REGFILEINT was used.

ENAMETOOLONG

The length of the pathname argument exceeds PATH_MAX, or a pathname component is longer than NAME_MAX and {_POSIX_NO_TRUNC} is in effect for that file. For symbolic links, the length of the pathname string substituted for a symbolic link exceeds PATH_MAX. PATH_MAX and NAME_MAX values can be determined by using pathconf().

ENODEV

The device does not exist. The function is not supported by the device driver.

ENOENT

Either there is no file named pathname or pathname is an empty string.

ENOTDIR

A component of the pathname prefix is not a directory.

ENOTSUP

Operation not supported. The following occurred:

Command _IOCC_REGFILEINT was used and fildes (w_ioctl) or pathname (__w_pioctl) refers to a file residing in a R/W file system that is shared across a sysplex with zFS, or is accessed through an NFS Client. In these cases, the file is able to be changed on a remote system without the local system being aware. Because the program would not receive notification, this operation is rejected.

Use __errno2() to obtain more diagnostic information.

ENOTTY

An incorrect file descriptor was specified. fildes was not a character special file.

If unsuccessful, w_ioctl() returns -1 and sets errno to one of the following values:

Error Code

Description

EBADF

The fildes parameter is not a valid file descriptor.

EINVAL

The request is invalid or not supported.

EMVSPARM

Incorrect parameters were passed to the service.

ENODEV

The device is incorrect. The function is not supported by the device driver.

CELEBW34

⁄* CELEBW34

   This example shows a general entry point for device-specific commands.

 *⁄
#include <termios.h>
#include <stdio.h>

main() {
  char buf[256];
  int  ret;

  memset(buf, 0x00, sizeof(buf));
  if ((ret = w_ioctl(0, 1, sizeof(buf), buf)) != 0)
    perror("w_ioctl() error");
  else
    printf("w_iotctl() returned '%s'\n", buf);
}

Output:

w_ioctl() error: Invalid argument