bsd/man/man2/getgroups.2

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  57 .\"     @(#)getgroups.2 8.2 (Berkeley) 4/16/94
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  59 .Dd October 2, 2008
  60 .Dt GETGROUPS 2
  61 .Os BSD 4.2
  62 .Sh NAME
  63 .Nm getgroups
  64 .Nd get group access list
  65 .Sh SYNOPSIS
  66 .Fd #include <unistd.h>
  67 .Ft int
  68 .Fo getgroups
  69 .Fa "int gidsetsize"
  70 .Fa "gid_t grouplist[]"
  71 .Fc
  72 .Sh DESCRIPTION
  73 .Fn getgroups
  74 gets the current group access list of the current user process
  75 and stores it in the array
  76 .Fa grouplist[] .
  77 The parameter
  78 .Fa gidsetsize
  79 indicates the number of entries that may be placed in
  80 .Fa grouplist[] .
  81 .Fn getgroups
  82 returns the actual number of groups returned in
  83 .Fa grouplist[] .
  84 However, no more than
  85 .Dv {NGROUPS_MAX}
  86 will be returned. If
  87 .Fa gidsetsize
  88 is 0,
  89 .Fn getgroups
  90 returns the number of groups without modifying the
  91 .Fa grouplist[]
  92 array.
  93 .Sh RETURN VALUES
  94 A successful call returns the number of groups in the group set.
  95 Otherwise, a value of -1 is returned and the global integer variable
  96 .Va errno
  97 is set to indicate the error.
  98 .Sh ERRORS
  99 The possible errors for
 100 .Fn getgroups
 101 are:
 102 .Bl -tag -width Er
 103 .\" ==========
 104 .It Bq Er EFAULT
 105 The argument
 106 .Fa grouplist
 107 specifies an invalid address.
 108 .\" ==========
 109 .It Bq Er EINVAL
 110 The argument
 111 .Fa gidsetsize ,
 112 although non-zero,
 113 is smaller than the number of groups in the group set.
 114 .El
 115 .Sh LEGACY DESCRIPTION
 116 If _DARWIN_C_SOURCE is defined,
 117 .Fn getgroups
 118 can return more than
 119 .Dv {NGROUPS_MAX}
 120 groups.
 121 .Sh LEGACY SYNOPSIS
 122 .Fd #include <sys/param.h>
 123 .Fd #include <sys/types.h>
 124 .Fd #include <unistd.h>
 125 .Pp
 126 The include files
 127 .In sys/param.h
 128 and
 129 .In sys/types.h
 130 are necessary.
 131 .Sh SEE ALSO
 132 .Xr setgroups 2 ,
 133 .Xr initgroups 3 ,
 134 .Xr compat 5
 135 .Sh HISTORY
 136 The
 137 .Fn getgroups
 138 function call appeared in
 139 .Bx 4.2 .