Difference between revisions of "Dbxfwd()"
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| Line 12: | Line 12: | ||
<input parameters> | <input parameters> | ||
| − | char *dbx; /* Tagged index file descriptor */ | + | char *dbx; /* Tagged index file descriptor */ |
<output parameters> | <output parameters> | ||
| Line 38: | Line 38: | ||
<code lang="c"> | <code lang="c"> | ||
#include <stdio.h> | #include <stdio.h> | ||
| − | #include "dbl.h" | + | #include "dbl.h" /* Recital/Library include file */ |
| − | #include "dblproto.h" /* Recital/Library prototype file */ | + | #include "dblproto.h" /* Recital/Library prototype file */ |
static dBFIELD fields[6] = { | static dBFIELD fields[6] = { | ||
"VESSEL", 'C', 18, 0, 0, | "VESSEL", 'C', 18, 0, 0, | ||
| − | "LAT", 'N', 4, 1, 0, | + | "LAT", 'N', 4, 1, 0, |
| − | "LONG", 'N', 4, 1, 0, | + | "LONG", 'N', 4, 1, 0, |
"AMOUNT", 'N', 10, 0, 0, | "AMOUNT", 'N', 10, 0, 0, | ||
| − | "DATE", 'D', 8, 0, 0, | + | "DATE", 'D', 8, 0, 0, |
| − | "FLAG", 'C', 9, 0, 0 | + | "FLAG", 'C', 9, 0, 0 |
}; | }; | ||
| Line 57: | Line 57: | ||
main() | main() | ||
{ | { | ||
| − | + | int rc; /* Return Code for error handling */ | |
| − | + | char *dbf; /* File descriptor for table */ | |
| − | + | char *dbx; /* File descriptor for tagged index */ | |
| − | + | int i; /* Loop control variable */ | |
| − | + | char record[58]; /* Array of char for records */ | |
| − | + | char nextkey[10][20]; /* Key buffers */ | |
| − | + | char status; /* Deleted record flag */ | |
| − | + | long rec_no[10]; /* Record number array */ | |
| − | + | rc = dbdcache(100); | |
| − | + | errorproc("dbdcache()","table cache specified.", rc); | |
| − | + | rc = dbicache(100); | |
| − | + | errorproc("dbicache()", "index cache specified.", rc); | |
| − | + | rc = dbfilemode(1,0); | |
| − | + | rc = dbopen("shipwreck.dbf", &dbf); | |
| − | + | errorproc("dbopen()","table opened in shared mode.", rc); | |
| − | + | rc = dbxopen(dbf, "shipwreck.dbx", &dbx); | |
| − | + | errorproc("dbxopen()","tagged index opened.", rc); | |
| − | + | rc = dbxfwd(dbx); | |
| − | + | errorproc("dbxfwd()", "index pointer placed at bottom.", rc); | |
| − | + | rc = dbxpkey(dbx, nextkey[0], rec_no); | |
| − | + | errorproc("dbxpkey()", "previous key found in tagged index.", rc); | |
| − | + | printf("\t\tprev key: \t%s\n", nextkey[0]); | |
| − | + | rc = dbxgetpr(dbf, dbx, record, &status); | |
| − | + | errorproc("dbxgetpr()", "previous record (by key) retrieved.", rc); | |
| − | + | printf("Previous: \t%s\n", record); | |
| − | + | rc = dbxrewind(dbx); | |
| − | + | errorproc("dbxrewind()", "Tagged index rewound.", rc); | |
| − | + | for( i = 1; i <= 6; i++) { | |
| − | + | rc = dbxgetnr(dbf, dbx, record, &status); | |
| − | + | printf("tt%d: %sn", i,record); | |
| − | + | } | |
| − | + | errorproc("dbxgetnr()", "6 records retrieved by tag key.", rc); | |
| − | + | rc = dbxnkey(dbx, nextkey[0], rec_no); | |
| − | + | errorproc("dbxnkey()", "next key retrieved in tagged index.", rc); | |
| − | + | printf("\t\tnext key: \t%s\n", nextkey[0]); | |
| − | + | rc = dbxclose(dbx); | |
| − | + | errorproc("dbxclose()", "tagged index closed.", rc); | |
| − | + | rc = dbclose(dbf); | |
| − | + | errorproc("dbclose()", "table closed.", rc); | |
| − | + | exit(0); | |
} | } | ||
| Line 114: | Line 114: | ||
{ | { | ||
if ( rc != SUCCESS ) { | if ( rc != SUCCESS ) { | ||
| − | + | printf("\n Error performing function %s -> %d\n", func, rc); | |
| − | + | exit(1); | |
} | } | ||
| − | printf("Function: t%s, t%s - | + | printf("Function: \t%s, \t%s - Ok\n", func, str); |
return; | return; | ||
} | } | ||
Revision as of 15:22, 5 May 2009
PURPOSE
position access pointer to end of active tag
SYNOPSIS
#include "dbl.h" int dbxfwd(dbx) <input parameters> char *dbx; /* Tagged index file descriptor */ <output parameters> none
RETURN VALUE
The dbxfwd() function returns to 0 for success, or < 0 if an error occurs. See the section on return code values for a detailed list of return codes.
DESCRIPTION
The dbxfwd() function positions the access pointer at the end of the active tag in the specified tagged index file, .DBX.
EXAMPLE
The following example opens the table and tag index, goes to the bottom of the index, reads the previous key by position then by key, rewinds the index, reads the next 6 records in the index, reads the next record by key and then closes the files.
#include <stdio.h> #include "dbl.h" /* Recital/Library include file */ #include "dblproto.h" /* Recital/Library prototype file */ static dBFIELD fields[6] = { "VESSEL", 'C', 18, 0, 0, "LAT", 'N', 4, 1, 0, "LONG", 'N', 4, 1, 0, "AMOUNT", 'N', 10, 0, 0, "DATE", 'D', 8, 0, 0, "FLAG", 'C', 9, 0, 0 }; static void errorproc( char *func, char *str, int rc); main() { int rc; /* Return Code for error handling */ char *dbf; /* File descriptor for table */ char *dbx; /* File descriptor for tagged index */ int i; /* Loop control variable */ char record[58]; /* Array of char for records */ char nextkey[10][20]; /* Key buffers */ char status; /* Deleted record flag */ long rec_no[10]; /* Record number array */ rc = dbdcache(100); errorproc("dbdcache()","table cache specified.", rc); rc = dbicache(100); errorproc("dbicache()", "index cache specified.", rc); rc = dbfilemode(1,0); rc = dbopen("shipwreck.dbf", &dbf); errorproc("dbopen()","table opened in shared mode.", rc); rc = dbxopen(dbf, "shipwreck.dbx", &dbx); errorproc("dbxopen()","tagged index opened.", rc); rc = dbxfwd(dbx); errorproc("dbxfwd()", "index pointer placed at bottom.", rc); rc = dbxpkey(dbx, nextkey[0], rec_no); errorproc("dbxpkey()", "previous key found in tagged index.", rc); printf("\t\tprev key: \t%s\n", nextkey[0]); rc = dbxgetpr(dbf, dbx, record, &status); errorproc("dbxgetpr()", "previous record (by key) retrieved.", rc); printf("Previous: \t%s\n", record); rc = dbxrewind(dbx); errorproc("dbxrewind()", "Tagged index rewound.", rc); for( i = 1; i <= 6; i++) { rc = dbxgetnr(dbf, dbx, record, &status); printf("tt%d: %sn", i,record); } errorproc("dbxgetnr()", "6 records retrieved by tag key.", rc); rc = dbxnkey(dbx, nextkey[0], rec_no); errorproc("dbxnkey()", "next key retrieved in tagged index.", rc); printf("\t\tnext key: \t%s\n", nextkey[0]); rc = dbxclose(dbx); errorproc("dbxclose()", "tagged index closed.", rc); rc = dbclose(dbf); errorproc("dbclose()", "table closed.", rc); exit(0); } static void errorproc(func, str, rc) char *func; char *str; int rc; { if ( rc != SUCCESS ) { printf("\n Error performing function %s -> %d\n", func, rc); exit(1); } printf("Function: \t%s, \t%s - Ok\n", func, str); return; }
