GNU dbm (gdbm) routines, version 1.7.3

GNU dbm is a set of database routines that use extendible hashing and
works similar to the standard UNIX dbm routines.  The basic unit of
data is the structure

  typedef struct {
             char *dptr;
             int   dsize;
          } datum;

GNU dbm allows multiple data files.  A routine that opens a gdbm file
is designated as a "reader" or a "writer".  Only one writer may open a
gdbm file and many readers may open the file.  Readers and writers can
not open the gdbm file at the same time.