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createlabel(3)
NAME
  createlabel - Creates a disk label structure for a disk device

LIBRARY
  Standard C Library (libc.a)

SYNOPSIS
  #include <sys/types.h>

  #include <sys/disklabel.h>

  int createlabel(
	  char *devname,
	  char *name,
	  struct disklabel *disk,
	  char *boot,
	  int boot_len);

PARAMETERS
  devname
      Specifies the device special file name of the device.

  name
      Specifies the name entry in the /etc/disktab file that is to be used
      for the label information.  Otherwise, specify NULL to indicate that
      the name entry either is not in the /etc/disktab file, or, if it is,
      that it should be ignored.

  disk
      Points to the disk label structure that is filled in with the returned
      disk description on successful completion of the function.

  boot
      Points to the buffer that the function may use to contain the
      (optional) primary and secondary bootstrap names for the disk label.

  boot_len
      Specifies the length of the boot buffer.	The value must be set to the
      value of the BUFSIZ constant.

DESCRIPTION
  The createlabel function fills in the disk label structure pointed to by
  the disk parameter.  The resulting disk label can then be written to the
  disk in order to label it.

  The function queries the device, using the devname parameter, to obtain the
  disk's geometry, capacity, and any default partition information.

  The function checks the name parameter.  If name is non-null, the function
  looks for an entry in the /etc/disktab file that matches the name string
  and initializes the disk label structure from that entry.  The function
  then overrides the device data and initializes the disk label structure
  from the entry in the /etc/disktab file.

  If the name string is NULL, or has no matching entry in the /etc/disktab
  file, the function queries the device (using the devname parameter) to
  obtain the device's name string.  The function then looks for an entry in
  the /etc/disktab file that matches that name string, and if it finds a
  match, initializes the disk label structure from that entry.

  If an /etc/disktab entry indicates that the device has a dynamic geometry,
  the function queries the device (using the devname parameter) to obtain the
  disk's true geometry and capacity and to override any value given in an
  /etc/disktab entry associated with the device.  In this case, any -1
  lengths encountered in the partition specifications for the entry are
  replaced by a value equal to the device's total capacity minus the starting
  offset of the partition.

RETURN VALUES
  Upon successful completion of the createlabel function, a value of 0 is
  returned and the contents of the disk label structure are updated.

  Upon error, a value of -1 is returned and errno is set to [EINVAL].

ERRORS
  [EINVAL]  Either disk or boot is NULL, or boot_len is not equal to BUFSIZ.

FILES
  /etc/disktab
	     Table of disk partition sizes for supported disks.

RELATED INFORMATION
  Commands: disklabel(8)

  Functions: getdiskbyname(3).

  Files: disklabel(4), disktab(4)

Index for Section 3

Alphabetical listing for C

Top of page