mdw@git.distorted.org.uk Git - qmail/blob - cdb.3

   1 .TH cdb 3
   2 .SH NAME
   3 cdb \- read from a constant database
   4 .SH SYNTAX
   5 .B #include <cdb.h>
   6
   7 int \fBcdb_seek(\fP\fIfd,key,len,dlen\fR\fB)\fP;
   8
   9 int \fIfd\fR;
  10 .br
  11 char *\fIkey\fR;
  12 .br
  13 unsigned int \fIlen\fR;
  14 .br
  15 uint32 *\fIdlen\fR;
  16 .SH DESCRIPTION
  17 .B cdb_seek
  18 looks up
  19 .I key
  20 in a constant database.
  21 It returns 1 if
  22 .I key
  23 is present,
  24 0 if
  25 .I key
  26 is not present,
  27 or \-1 if there was a read error.
  28 .I key
  29 is an array of
  30 .I len
  31 characters.
  32
  33 .B cdb_seek
  34 needs an open file descriptor,
  35 .IR fd ,
  36 pointing to the database.
  37 If
  38 .B cdb_seek
  39 returns 1,
  40 it points
  41 .I fd
  42 at the beginning of the data portion of the first record
  43 indexed by
  44 .IR key ,
  45 and it stores the data length in
  46 .IR dlen.
  47 .B cdb_seek
  48 does not provide a way to read subsequent records with the same key.
  49
  50 It's fine to do several
  51 .B cdb_seek
  52 lookups with the same open file descriptor.
  53 Beware, however, that two simultaneous
  54 .B cdb_seek
  55 lookups can fail horribly;
  56 separate processes should not share the same database descriptor.
  57 Furthermore, any updates after the database was opened
  58 will be invisible.
  59 It's rarely a good idea for a long-running program
  60 to hold a database open.
  61 .SH "SEE ALSO"
  62 cdbget(1)