compress/zopen.3

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  32 .\"     @(#)zopen.3     8.1 (Berkeley) 6/9/93
  33 .\" $FreeBSD: src/usr.bin/compress/zopen.3,v 1.8 2001/10/01 15:01:57 ru Exp $
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  35 .Dd June 9, 1993
  36 .Dt ZOPEN 3
  37 .Os
  38 .Sh NAME
  39 .Nm zopen
  40 .Nd compressed stream open function
  41 .Sh SYNOPSIS
  42 .Fd #include \&"zopen.h\&"
  43 .Ft FILE *
  44 .Fn zopen "const char *path" "const char *mode" "int bits"
  45 .Sh DESCRIPTION
  46 The
  47 .Fn zopen
  48 function
  49 opens the compressed file whose name is the string pointed to by
  50 .Fa path
  51 and associates a stream with it.
  52 .Pp
  53 The argument
  54 .Fa mode
  55 points to one of the following one-character strings:
  56 .Bl -tag -width indent
  57 .It Dq Li r
  58 Open compressed file for reading.
  59 The stream is positioned at the beginning of the file.
  60 .It Dq Li w
  61 Truncate file to zero length or create compressed file for writing.
  62 The stream is positioned at the beginning of the file.
  63 .El
  64 .Pp
  65 Any created files will have mode
  66 .Pf \\*q Dv S_IRUSR
  67 \&|
  68 .Dv S_IWUSR
  69 \&|
  70 .Dv S_IRGRP
  71 \&|
  72 .Dv S_IWGRP
  73 \&|
  74 .Dv S_IROTH
  75 \&|
  76 .Dv S_IWOTH Ns \\*q
  77 .Pq Li 0666 ,
  78 as modified by the process'
  79 umask value (see
  80 .Xr umask 2 ) .
  81 .Pp
  82 Files may only be read or written.
  83 Seek operations are not allowed.
  84 .Pp
  85 The
  86 .Fa bits
  87 argument, if non-zero, is set to the bits code limit.
  88 If zero, the default is 16.
  89 See
  90 .Xr compress 1
  91 for more information.
  92 .Sh RETURN VALUES
  93 Upon successful completion
  94 .Fn zopen
  95 returns a
  96 .Tn FILE
  97 pointer.
  98 Otherwise,
  99 .Dv NULL
 100 is returned and the global variable
 101 .Va errno
 102 is set to indicate the error.
 103 .Sh ERRORS
 104 .Bl -tag -width [EINVAL]
 105 .It Bq Er EINVAL
 106 The
 107 .Fa mode
 108 or
 109 .Fa bits
 110 arguments specified to
 111 .Fn zopen
 112 were invalid.
 113 .It Bq Er EFTYPE
 114 The compressed file starts with an invalid header, or the compressed
 115 file is compressed with more bits than can be handled.
 116 .El
 117 .Pp
 118 The
 119 .Fn zopen
 120 function may also fail and set
 121 .Va errno
 122 for any of the errors specified for the routines
 123 .Xr fopen 3
 124 or
 125 .Xr funopen 3 .
 126 .Sh SEE ALSO
 127 .Xr compress 1 ,
 128 .Xr fopen 3 ,
 129 .Xr funopen 3
 130 .Sh HISTORY
 131 The
 132 .Nm
 133 function
 134 first appeared in
 135 .Bx 4.4 .
 136 .Sh BUGS
 137 The
 138 .Fn zopen
 139 function
 140 may not be portable to systems other than
 141 .Bx .