1 .TH VENTI-LOG 3
2 .SH NAME
3 VtLog,
4 VtLogChunk, 
5 vtlog,
6 vtlogclose,
7 vtlogdump,
8 vtlognames,
9 vtlogopen,
10 vtlogprint,
11 vtlogremove,
12 vtlogopen,
13 ventilogging \- Venti logs
14 .SH SYNOPSIS
15 .ft L
16 #include <u.h>
17 .br
18 #include <libc.h>
19 .br
20 #include <venti.h>
21 .ta +\w'\fLVtLog* 'u
22 .PP
23 .B
24 VtLog*	vtlogopen(char *name, uint size);
25 .PP
26 .B
27 void	vtlogprint(VtLog *log, char *fmt, ...);
28 .PP
29 .B
30 void	vtlogclose(VtLog *log);
31 .PP
32 .B
33 void	vtlog(char *name, char *fmt, ...);
34 .PP
35 .B
36 void	vtlogremove(char *name);
37 .PP
38 .B
39 char**	vtlognames(int *n);
40 .PP
41 .B
42 void	vtlogdump(int fd, VtLog *log);
43 .PP
44 .B
45 extern int ventilogging;    /* default 0 */
46 .PP
47 .B
48 extern char *VtServerLog;    /* "libventi/server" */
49 .SH DESCRIPTION
50 These routines provide an in-memory circular log
51 structure used by the Venti library and the Venti server
52 to record events for debugging purposes.
53 The logs are named by UTF strings.
54 .PP
55 .I Vtlogopen
56 returns a reference to the log with the given
57 .I name .
58 If a log with that name does not exist and
59 .I size 
60 is non-zero,
61 .I vtlogopen
62 creates a new log capable of holding at
63 least
64 .I size
65 bytes and returns it.
66 .I Vtlogclose
67 releases the reference returned by
68 .IR vtlogopen .
69 .PP
70 .I Vtlogprint
71 writes to
72 .IR log ,
73 which must be open.
74 .PP
75 .I Vtlog
76 is a convenient packaging of
77 .I vtlogopen
78 followed by
79 .I vtlogprint
80 and
81 .IR vtlogclose .
82 .PP
83 .I Vtlogremove
84 removes the log with the given
85 .IR name ,
86 freeing any associated storage.
87 .PP
88 .I Vtlognames
89 returns a list of the names of all the logs.
90 The length of the list is returned in
91 .BI * n \fR.
92 The list
93 should be freed
94 by calling
95 .I vtfree
96 on the returned pointer.
97 The strings in the list will be freed by this call as well.
98 (It is an error to call
99 .I vtfree
100 on any of the strings in the list.)
101 .PP
102 .I Vtlogdump
103 prints
104 .IR log ,
105 which must be open, to the file descriptor
106 .IR fd .
107 .PP
108 If
109 .I ventilogging
110 is set to zero (the default),
111 .I vtlognames
112 and
113 .I vtlogdump
114 can inspect existing logs, but
115 .I vtlogopen
116 always returns nil
117 and
118 .I vtlog
119 is a no-op.
120 The other functions are no-ops when
121 passed nil log structures.
122 .PP
123 The server library
124 (see
125 .MR venti-conn (3)
126 and
127 .MR venti-server (3) )
128 writes debugging information to the log named
129 .IR VtServerLog ,
130 which defaults to the string
131 .RB ` libventi/server '.
132 .SH SOURCE
133 .B \*9/src/libventi
134 .SH SEE ALSO
135 .MR venti (3) ,
136 .MR venti (8)