1QBRB.H(3)                  libqb Programmer's Manual                 QBRB.H(3)
2
3
4

NAME

6       qbrb.h  -  This  implements  a  ring buffer that works in "chunks", not
7       bytes.
8
9

SYNOPSIS

11       #include <qb/qbrb.h>
12

DESCRIPTION

14       So you write/read a complete chunk or not at all. There are  two  types
15       of ring buffer: normal and overwrite. Overwrite will reclaim the oldest
16       chunks inorder to make way for new ones, the normal version will refuse
17       to write a new chunk if the ring buffer is full.
18
19       This  implementation  is  capable  of working across processes, but one
20       process must only write and the other process read.
21
22       The read process will do the following:
23
24            rb = qb_rb_open("test2", 2000, QB_RB_FLAG_SHARED_PROCESS|QB_RB_FLAG_CREATE);
25            for (i = 0; i < 200; i++) {
26       try_read_again:
27               l = qb_rb_chunk_read(rb, (void *)out, 32, 1000);
28               if (l < 0) {
29                       goto try_read_again;
30               }
31            }
32            ...
33            qb_rb_close(rb);
34
35
36       The write process will do the following:
37
38            rb = qb_rb_open("test2", 2000, QB_RB_FLAG_SHARED_PROCESS);
39            for (i = 0; i < 200; i++) {
40       try_write_again:
41               l = qb_rb_chunk_write(rb, &v, sizeof(v));
42               if (l < sizeof(v)) {
43                       goto try_write_again;
44               }
45            }
46            ...
47            qb_rb_close(rb);
48
49

SEE ALSO

51       qb_rb_close(3), qb_rb_refcount_get(3), qb_rb_chmod(3), qb_rb_chown(3),
52       qb_rb_open(3), qb_rb_write_to_file(3), qb_rb_create_from_file(3),
53       qb_rb_chunks_used(3), qb_rb_chunk_reclaim(3), qb_rb_space_used(3),
54       qb_rb_chunk_write(3), qb_rb_shared_user_data_get(3),
55       qb_rb_chunk_commit(3), qb_rb_chunk_peek(3), qb_rb_space_free(3),
56       qb_rb_name_get(3), qb_rb_chunk_alloc(3), qb_rb_chunk_read(3)
57

59       Copyright (C) 2010-2020 Red Hat, Inc.
60
61
62
63LIBQB                             2021-11-12                         QBRB.H(3)
Impressum