gen/FreeBSD/setmode.3

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  28 .\"     @(#)setmode.3   8.2 (Berkeley) 4/28/95
  29 .\" $FreeBSD: src/lib/libc/gen/setmode.3,v 1.12 2007/01/09 00:27:55 imp Exp $
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  31 .Dd April 28, 1995
  32 .Dt SETMODE 3
  33 .Os
  34 .Sh NAME
  35 .Nm getmode ,
  36 .Nm setmode
  37 .Nd modify mode bits
  38 .Sh LIBRARY
  39 .Lb libc
  40 .Sh SYNOPSIS
  41 .In unistd.h
  42 .Ft mode_t
  43 .Fn getmode "const void *set" "mode_t mode"
  44 .Ft void *
  45 .Fn setmode "const char *mode_str"
  46 .Sh DESCRIPTION
  47 The
  48 .Fn getmode
  49 function
  50 returns a copy of the file permission bits
  51 .Fa mode
  52 as altered by the values pointed to by
  53 .Fa set .
  54 While only the mode bits are altered, other parts of the file mode
  55 may be examined.
  56 .Pp
  57 The
  58 .Fn setmode
  59 function
  60 takes an absolute (octal) or symbolic value, as described in
  61 .Xr chmod 1 ,
  62 as an argument
  63 and returns a pointer to mode values to be supplied to
  64 .Fn getmode .
  65 Because some of the symbolic values are relative to the file
  66 creation mask,
  67 .Fn setmode
  68 may call
  69 .Xr umask 2 .
  70 If this occurs, the file creation mask will be restored before
  71 .Fn setmode
  72 returns.
  73 If the calling program changes the value of its file creation mask
  74 after calling
  75 .Fn setmode ,
  76 .Fn setmode
  77 must be called again if
  78 .Fn getmode
  79 is to modify future file modes correctly.
  80 .Pp
  81 If the mode passed to
  82 .Fn setmode
  83 is invalid or if memory cannot be allocated for the return value,
  84 .Fn setmode
  85 returns
  86 .Dv NULL .
  87 .Pp
  88 The value returned from
  89 .Fn setmode
  90 is obtained from
  91 .Fn malloc
  92 and should be returned to the system with
  93 .Fn free
  94 when the program is done with it, generally after a call to
  95 .Fn getmode .
  96 .Sh ERRORS
  97 The
  98 .Fn setmode
  99 function
 100 may fail and set errno for any of the errors specified for the library
 101 routine
 102 .Xr malloc 3 .
 103 .Sh SEE ALSO
 104 .Xr chmod 1 ,
 105 .Xr stat 2 ,
 106 .Xr umask 2 ,
 107 .Xr malloc 3
 108 .Sh HISTORY
 109 The
 110 .Fn getmode
 111 and
 112 .Fn setmode
 113 functions first appeared in
 114 .Bx 4.4 .