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getgroups(2)
NAME
  getgroups - Get 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 Open Group standards, but might 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(): XSH4.0, XSH4.2, XSH5.0

  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 supplementary group IDs of the
	  process are stored. The effective group ID of the process is not
	  returned by the getgroups() function if it is not also a
	  supplementary group ID of the calling 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 IDs than the value indicated by
  the sysconf() parameter _SC_NGROUPS_MAX.

  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.

SEE ALSO
  Commands: groups(1)

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

  Standards: standards(5)

Index for Section 2

Alphabetical listing for G

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