Difference between revisions of "Dbpkey()"
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<input parameter> | <input parameter> | ||
| − | char *ndx; /* Address of the .NDX file descriptor from which to read a key | + | char *ndx; /* Address of the .NDX file descriptor from which to read a key */ |
<output parameters> | <output parameters> | ||
| − | char *key; /* Address of the buffer where the key is stored by the function | + | char *key; /* Address of the buffer where the key is stored by the function */ |
| − | long *recno; /* Address of the variable where the corresponding record number is stored by the function */ | + | long *recno; /* Address of the variable where the corresponding record number is stored by the function */ |
</code> | </code> | ||
| Line 37: | Line 37: | ||
#include <dbl.h> | #include <dbl.h> | ||
| − | char *ndx; | + | char *ndx; /* .NDX file descriptor */ |
| − | char prevkey[8]; | + | char prevkey[8]; /* Key buffer */ |
| − | long recno; | + | long recno; /* Record no. associated with key */ |
| − | int rc; /* Return code | + | int rc; /* Return code */ |
rc = dbpkey(ndx, prevkey, &recno); | rc = dbpkey(ndx, prevkey, &recno); | ||
else { | else { | ||
| − | printf("error number %d n, rc); | + | printf("error number %d \n, rc); |
exit (1); | exit (1); | ||
} | } | ||
Revision as of 14:00, 1 May 2009
PURPOSE
read previous key
SYNOPSIS
#include "dbl.h" int dbpkey(ndx, key, recno) <input parameter> char *ndx; /* Address of the .NDX file descriptor from which to read a key */ <output parameters> char *key; /* Address of the buffer where the key is stored by the function */ long *recno; /* Address of the variable where the corresponding record number is stored by the function */
RETURN VALUE
The dbpkey() function returns 0 for success, or < 0 if an error occurs. See the section on return code values for a detailed list of return codes.
DESCRIPTION
This function sequentially reads the previous key in a descending (or counter-alphabetical) order and its associated record number from the .NDX file whose file descriptor is passed to the function.
EXAMPLE
This example reads the previous key and its associated record number from a .NDX file whose file descriptor is in "char *ndx". The key and record number are stored in "char prevkey[18];" and "long recno;" respectively. The key is assumed to be date or numeric.
#include <dbl.h> char *ndx; /* .NDX file descriptor */ char prevkey[8]; /* Key buffer */ long recno; /* Record no. associated with key */ int rc; /* Return code */ rc = dbpkey(ndx, prevkey, &recno); else { printf("error number %d \n, rc); exit (1); }
SEE ALSO
dbckey(), dbkeytoa(), dbfwd(), dbgetpr(), dbnkey(), dbrewind()
