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getgroups(2)
NAME
  getgroups - Gets the supplementary group IDs of the current process

SYNOPSIS
  #include <unistd.h>

  int getgroups(
	  int gidsetsize,
	  gid_t grouplist[]);

  Application developers may want to specify an #include statement for
  <sys/types.h> before the one for <unistd.h> if programs are being developed
  for multiple platforms. The additional #include statement is not required
  on Tru64 UNIX systems or by ISO or X/Open standards, but may be required on
  other vendors' systems that conform to these standards.

STANDARDS
  Interfaces documented on this reference page conform to industry standards
  as follows:

  getgroups(): XSH4.2

  Refer to the standards(5) reference page for more information about
  industry standards and associated tags.

PARAMETERS
  gidsetsize
	    Indicates the number of entries that can be stored in the array
	    pointed to by the grouplist parameter.

  grouplist Points to the array in which the process' supplementary group IDs
	    are stored.	 Element grouplist[0] is the effective group ID of
	    the process.

DESCRIPTION
  The getgroups() function gets the current supplementary group IDs of the
  calling process.  The list is stored in the array pointed to by the
  grouplist parameter.	The gidsetsize parameter indicates the number of
  entries that can be stored in this array.

  The getgroups() function never returns more than NGROUPS_MAX entries.
  (NGROUPS_MAX is a constant defined in the limits.h header file.) If the
  gidsetsize parameter is 0 (zero), the getgroups() function returns the
  number of supplementary group IDs associated with the calling process
  without modifying the array pointed to by grouplist.




RETURN VALUES
  Upon successful completion, the getgroups() function returns the number of
  elements stored in the array pointed to by the grouplist parameter.
  Otherwise, the function returns a value of -1 and sets errno to indicate
  the error.

ERRORS
  If the getgroups() function fails, errno might be set to one of the
  following values:

  [EFAULT]  [Tru64 UNIX]  The gidsetsize and grouplist parameters specify an
	    array that is partially or completely outside of the allocated
	    address space of the process.

  [EINVAL]  The gidsetsize parameter is nonzero and smaller than the number
	    of supplementary group IDs.

RELATED INFORMATION
  Commands: groups(1)

  Functions: setgroups(2), getgid(2), setsid(2), initgroups(3)

  Standards: standards(5)

Index for Section 2

Alphabetical listing for G

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