Difference between revisions of "Dbxtag()"
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The dbxtag() 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. | The dbxtag() 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. | ||
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==DESCRIPTION== | ==DESCRIPTION== | ||
Revision as of 12:16, 1 April 2009
PURPOSE
change the active tag
SYNOPSIS
#include "dbl.h" int dbxtag(dbx, tagname) <input parameters> char *dbx /* Tagged index file descriptor */ char *tagname /* Address of a buffer containing the tag to make active */ <output parameters> none
RETURN VALUE
The dbxtag() 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
The dbxtag() function changes the active tag in the specified tag file, .DBX. All dbx functions in this library perform their operations on the active tag.
EXAMPLE
The following example creates the shipwreck table and tags on the VESSEL and FLAG fields. It appends a record, reads the current key using the default VESSEL tag then changes the active tag to FLAG and reads the current key.
#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); static char *text_table[] = { "Santa Margarita 80.027.5 700000095/01/01Spanish " }; main() { int rc; /* Return Code for error handling */ char *dbf; /* File descriptor for table */ char *dbx; /* File descriptor for tagged index */ FLDNUM fieldcount; /* Number of fields to create */ int i; /* Loop control variable */ long recno; /* Table record variable */ char key[21]; /* Storage location for keys */ rc = dbdcache(100); errorproc("dbdcache()","table cache specified.", rc); rc = dbicache(100); errorproc("dbicache()", "index cache specified.", rc); rc = dbfilemode(0,0); fieldcount = 6; rc = dbcreat("shipwreck.dbf", fieldcount, fields); errorproc("dbcreat()","database created.", rc); rc = dbopen("shipwreck.dbf", &dbf); errorproc("dbopen()","table opened.", rc); rc = dbxcreate( dbf, fields[0].fieldnm, /* "VESSEL", */ &dbx, fields[0].fieldnm, /* "VESSEL", */ NULL, 0, 0); errorproc("dbxcreate()","tag created", rc); rc = dbxcreate( dbf, fields[5].fieldnm, /* "FLAG", */ &dbx, fields[5].fieldnm, /* "FLAG", */ NULL, 0, 0); errorproc("dbxcreate()","tag created", rc); rc = dbxclose(dbx); errorproc("dbxclose()", "tagged index closed.", rc); rc = dbxopen(dbf, "shipwreck.dbx", &dbx); errorproc("dbxopen()","tagged index opened.", rc); rc = dbappend(dbf, text_table[0], &recno); errorproc("dbappend()", "record appended.", rc); rc = dbxakey(dbx, recno); errorproc("dbxakey()", "key added.", rc); rc = dbflush(dbf); errorproc("dbflush()", "table cache flushed.", rc); rc = dbxflsh(dbx); errorproc("dbxflsh()", "tagged index cache flushed.", rc); rc = dbxckey(dbx, key, &recno); errorproc("dbxckey()", "current key read.", rc); printf("ttcurrent key: t%sn", key); rc = dbxtag(dbx, fields[5].fieldnm); errorproc("dbxtag()", "current tag changed to flag.", rc); rc = dbxckey(dbx, key, &recno); errorproc("dbxckey()", "current key read.", rc); printf("ttcurrent key: t%sn", key); 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 -> %dn", func, rc); exit(1); } printf("Function: t%s, t%s - Okn", func, str); return; }
