1ARCHIVE_READ_OPEN(3) BSD Library Functions Manual ARCHIVE_READ_OPEN(3)
2
4 archive_read_open, archive_read_open2, archive_read_open_fd,
5 archive_read_open_FILE, archive_read_open_filename,
6 archive_read_open_memory — functions for reading streaming archives
7
9 Streaming Archive Library (libarchive, -larchive)
10
12 #include <archive.h>
13
14 int
15 archive_read_open(struct archive *, void *client_data,
16 archive_open_callback *, archive_read_callback *,
17 archive_close_callback *);
18
19 int
20 archive_read_open2(struct archive *, void *client_data,
21 archive_open_callback *, archive_read_callback *,
22 archive_skip_callback *, archive_close_callback *);
23
24 int
25 archive_read_open_FILE(struct archive *, FILE *file);
26
27 int
28 archive_read_open_fd(struct archive *, int fd, size_t block_size);
29
30 int
31 archive_read_open_filename(struct archive *, const char *filename,
32 size_t block_size);
33
34 int
35 archive_read_open_memory(struct archive *, const void *buff,
36 size_t size);
37
39 archive_read_open()
40 The same as archive_read_open2(), except that the skip callback
41 is assumed to be NULL.
42 archive_read_open2()
43 Freeze the settings, open the archive, and prepare for reading
44 entries. This is the most generic version of this call, which
45 accepts four callback functions. Most clients will want to use
46 archive_read_open_filename(), archive_read_open_FILE(),
47 archive_read_open_fd(), or archive_read_open_memory() instead.
48 The library invokes the client-provided functions to obtain raw
49 bytes from the archive.
50 archive_read_open_FILE()
51 Like archive_read_open(), except that it accepts a FILE *
52 pointer. This function should not be used with tape drives or
53 other devices that require strict I/O blocking.
54 archive_read_open_fd()
55 Like archive_read_open(), except that it accepts a file descrip‐
56 tor and block size rather than a set of function pointers. Note
57 that the file descriptor will not be automatically closed at end-
58 of-archive. This function is safe for use with tape drives or
59 other blocked devices.
60 archive_read_open_file()
61 This is a deprecated synonym for archive_read_open_filename().
62 archive_read_open_filename()
63 Like archive_read_open(), except that it accepts a simple file‐
64 name and a block size. A NULL filename represents standard
65 input. This function is safe for use with tape drives or other
66 blocked devices.
67 archive_read_open_memory()
68 Like archive_read_open(), except that it accepts a pointer and
69 size of a block of memory containing the archive data.
70
71 A complete description of the struct archive and struct archive_entry
72 objects can be found in the overview manual page for libarchive(3).
73
75 The callback functions must match the following prototypes:
76
77 typedef la_ssize_t archive_read_callback(struct archive *,
78 void *client_data, const void **buffer)
79
80 typedef la_int64_t archive_skip_callback(struct archive *,
81 void *client_data, off_t request)
82
83 typedef int archive_open_callback(struct archive *, void
84 *client_data)
85
86 typedef int archive_close_callback(struct archive *, void
87 *client_data)
88
89 The open callback is invoked by archive_open(). It should return
90 ARCHIVE_OK if the underlying file or data source is successfully opened.
91 If the open fails, it should call archive_set_error() to register an
92 error code and message and return ARCHIVE_FATAL.
93
94 The read callback is invoked whenever the library requires raw bytes from
95 the archive. The read callback should read data into a buffer, set the
96 const void **buffer argument to point to the available data, and return a
97 count of the number of bytes available. The library will invoke the read
98 callback again only after it has consumed this data. The library imposes
99 no constraints on the size of the data blocks returned. On end-of-file,
100 the read callback should return zero. On error, the read callback should
101 invoke archive_set_error() to register an error code and message and
102 return -1.
103
104 The skip callback is invoked when the library wants to ignore a block of
105 data. The return value is the number of bytes actually skipped, which
106 may differ from the request. If the callback cannot skip data, it should
107 return zero. If the skip callback is not provided (the function pointer
108 is NULL ), the library will invoke the read function instead and simply
109 discard the result. A skip callback can provide significant performance
110 gains when reading uncompressed archives from slow disk drives or other
111 media that can skip quickly.
112
113 The close callback is invoked by archive_close when the archive process‐
114 ing is complete. The callback should return ARCHIVE_OK on success. On
115 failure, the callback should invoke archive_set_error() to register an
116 error code and message and return ARCHIVE_FATAL.
117
119 These functions return ARCHIVE_OK on success, or ARCHIVE_FATAL.
120
122 Detailed error codes and textual descriptions are available from the
123 archive_errno() and archive_error_string() functions.
124
126 tar(1), archive_read(3), archive_read_data(3), archive_read_filter(3),
127 archive_read_format(3), archive_read_set_options(3), archive_util(3),
128 libarchive(3), tar(5)
129
130BSD February 2, 2012 BSD