SYNTAX

       #include "cdbread.h"

       void cdb_init(struct cdb *c,int fd);
       int cdb_read(struct cdb *c,char *data,unsigned int dlen,uint32 pos);
       int cdb_findstart(int fd,char *key,unsigned int len);
       int cdb_findnext(int fd,char *key,unsigned int len);
       int cdb_find(int fd,char *ney,unsigned int len);

       int cdb_findnext(int fd,char *key,unsigned int len);
       void cdb_free(struct cdb *c):

DESCRIPTION

       cdb_free unallocates c if c is allocated.  Otherwise it leaves c alone.
       cdb_free does not close fd.

       cdb_init allocates c to hold information about a constant database read
       by descriptor fd.  You may call cdb_init repeatedly; if c is already
       allocated, cdb_init unallocates it first.

       cdb_read reads dlen bytes into d from byte position dpos in the
       database. You must allocate c before calling cdb_read.  Normally
       cdb_read returns 0.  If the database file is shorter than dpos+dlen
       bytes, or if there is a disk read error, cdb_read returns -1, setting
       errno appropriately.

       cdb_findstart prepares c to search for the first record under a new
       key.  You must allocate c before calling cdb_findstart, and you must
       call cdb_findstart before calling cdb_findnext.

       cdb_findnext looks for the nth record under key in the database, where
       n is the number of calls to cdb_findnext after the most recent call to
       cdb_findstart.  If it finds the record, cdb_findnext returns 1; if
       there are exactly n-1 such records, cdb_findnext returns 0; if there
       are fewer than n-1 such records, the behavior of cdb_findnext is
       undefined; if there is a database format error or disk error,
       cdb_findnext returns -1,setting errno appropriately. Each call to
       cdb_findnext (before another call to cdb_findstart) must use the same k
       and klen.

       If cdb_findnext returns 1, it arranges for cdb_datapos to return the
       starting byte position of the data in the record, and for cdb_datalen
       to return the number of bytes of data in the record.  Otherwise the
       results of cdb_datapos and cdb_datalen are undefined.

       cdb_find is the same as cdb_findstart followed by cdb_findnext: it
       finds the first record under key.

       cdb_datapos and cdb_datalen are macros pointing to the found
       information following key in the cdb and returning their length.

EXAMPLE

         }

         len = cdb_datalen(&c);
         data = alloc(len);
         if (!data) return -1;

         if (cdb_read(&c,data,datalen,cdb_datapos(&c)) == -1) {
           alloc_free(data);
           return -1;
         }

         cdb_free(&c);

SEE ALSO

       cdbmake(3)



                                                              qlibs:cdbread(3)