xref: /freebsd/usr.bin/compress/zopen.3 (revision 8ddb146abcdf061be9f2c0db7e391697dafad85c)
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28.\"	@(#)zopen.3	8.1 (Berkeley) 6/9/93
29.\" $FreeBSD$
30.\"
31.Dd June 9, 1993
32.Dt ZOPEN 3
33.Os
34.Sh NAME
35.Nm zopen
36.Nd compressed stream open function
37.Sh SYNOPSIS
38.Fd #include \&"zopen.h\&"
39.Ft FILE *
40.Fn zopen "const char *path" "const char *mode" "int bits"
41.Sh DESCRIPTION
42The
43.Fn zopen
44function
45opens the compressed file whose name is the string pointed to by
46.Fa path
47and associates a stream with it.
48.Pp
49The argument
50.Fa mode
51points to one of the following one-character strings:
52.Bl -tag -width indent
53.It Dq Li r
54Open compressed file for reading.
55The stream is positioned at the beginning of the file.
56.It Dq Li w
57Truncate file to zero length or create compressed file for writing.
58The stream is positioned at the beginning of the file.
59.El
60.Pp
61Any created files will have mode
62.Pf \\*q Dv S_IRUSR
63\&|
64.Dv S_IWUSR
65\&|
66.Dv S_IRGRP
67\&|
68.Dv S_IWGRP
69\&|
70.Dv S_IROTH
71\&|
72.Dv S_IWOTH Ns \\*q
73.Pq Li 0666 ,
74as modified by the process'
75umask value (see
76.Xr umask 2 ) .
77.Pp
78Files may only be read or written.
79Seek operations are not allowed.
80.Pp
81The
82.Fa bits
83argument, if non-zero, is set to the bits code limit.
84If zero, the default is 16.
85See
86.Xr compress 1
87for more information.
88.Sh RETURN VALUES
89Upon successful completion
90.Fn zopen
91returns a
92.Tn FILE
93pointer.
94Otherwise,
95.Dv NULL
96is returned and the global variable
97.Va errno
98is set to indicate the error.
99.Sh ERRORS
100.Bl -tag -width [EINVAL]
101.It Bq Er EINVAL
102The
103.Fa mode
104or
105.Fa bits
106arguments specified to
107.Fn zopen
108were invalid.
109.It Bq Er EFTYPE
110The compressed file starts with an invalid header, or the compressed
111file is compressed with more bits than can be handled.
112.El
113.Pp
114The
115.Fn zopen
116function may also fail and set
117.Va errno
118for any of the errors specified for the routines
119.Xr fopen 3
120or
121.Xr funopen 3 .
122.Sh SEE ALSO
123.Xr compress 1 ,
124.Xr fopen 3 ,
125.Xr funopen 3
126.Sh HISTORY
127The
128.Nm
129function
130first appeared in
131.Bx 4.4 .
132.Sh BUGS
133The
134.Fn zopen
135function
136may not be portable to systems other than
137.Bx .
138