[ << ] | [ < ] | [ Up ] | [ > ] | [ >> ] | [Top] | [Contents] | [Index] | [ ? ] |
8 Searching for records in the database.
- gdbm interface: datum gdbm_fetch (GDBM_FILE dbf, datum key)
Looks up a given key and returns the information associated with it. The ‘dptr’ field in the structure that is returned points to a memory block allocated by
malloc
. It is the caller’s responsibility to free it when no longer needed.If the ‘dptr’ is ‘NULL’, no data was found.
The parameters are:
- dbf
The pointer returned by
gdbm_open
.- key
The search key.
An example of using this function:
content = gdbm_fetch (dbf, key); if (content.dptr == NULL) { fprintf(stderr, "key not found\n"); } else { /* do something with content.dptr */ }
You may also search for a particular key without retrieving it:
- gdbm interface: int gdbm_exists (GDBM_FILE dbf, datum key)
Returns ‘true’ (‘1’) if the key exists in dbf and ‘false’ (‘0’) otherwise.
The parameters are:
- dbf
The pointer returned by
gdbm_open
.- key
The search key.
This document was generated on January 24, 2014 using texi2html 5.0.