Difference between revisions of "Dbkexpr()"
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<input parameters> | <input parameters> | ||
| − | char *ndx; /* .NDX file descriptor | + | char *ndx; /* .NDX file descriptor */ |
<output parameters> | <output parameters> | ||
| − | char keytype; /* Index key data type: | + | char keytype; /* Index key data type: |
| − | + | 'C' – CHARACTER | |
| − | + | 'N' – NUMERIC | |
| − | + | 'D' – DATE */ | |
| − | char *keyexpr; /* Index key expression | + | char *keyexpr; /* Index key expression */ |
| − | int *kexprlen; /* Length of index key expression */ | + | int *kexprlen; /* Length of index key expression */ |
| − | int *keylen; /* Index key length | + | int *keylen; /* Index key length */ |
</code> | </code> | ||
| Line 46: | Line 46: | ||
#include "dbl.h" | #include "dbl.h" | ||
| − | char *ndx; | + | char *ndx; /* .NDX file descriptor */ |
char keytype; /* Key type */ | char keytype; /* Key type */ | ||
| − | char keyexpr[512]; | + | char keyexpr[512]; /* Index key expression */ |
| − | int keyexprlen; | + | int keyexprlen; /* Expression length */ |
| − | int keylen; | + | int keylen; /* Key length */ |
int rc; /* Return code */ | int rc; /* Return code */ | ||
| − | rc = dbkexpr(ndx, &keytype, keyexpr, &keyexprlen, | + | rc = dbkexpr(ndx, &keytype, keyexpr, &keyexprlen, &keylen); |
| − | + | if (rc == SUCCESS){ | |
| − | if (rc = = SUCCESS){ | + | printf("\t Index file information - \n"); |
| − | printf("t Index file information - n"); | + | printf("\t \t type = '%c', keyexpression = '%s', |
| − | printf("t t type = '%c', keyexpression = '%s', | + | exprlen = %d, keylen = %d \n". keytype, |
| − | exprlen = %d, keylen = %d n". keytype, | + | |
keyexpr, keyexprlen, keylen); | keyexpr, keyexprlen, keylen); | ||
} else { | } else { | ||
| − | printf("error number %d n", rc); | + | printf("error number %d \n", rc); |
exit (1); | exit (1); | ||
} | } | ||
Revision as of 13:31, 1 May 2009
PURPOSE
get key expression
SYNOPSIS
#include "dbl.h" int dbkexpr(ndx, keytype, keyexpr, keyprlen, keylen) <input parameters> char *ndx; /* .NDX file descriptor */ <output parameters> char keytype; /* Index key data type: 'C' – CHARACTER 'N' – NUMERIC 'D' – DATE */ char *keyexpr; /* Index key expression */ int *kexprlen; /* Length of index key expression */ int *keylen; /* Index key length */
RETURN VALUE
The dbkexpr() 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 obtains the index information from the specified .NDX file. This information includes:
- index key data type('C' for CHARACTER keys, 'N' for NUMERIC and 'D' for DATE),
- index key expression (usually a character string consisting of one or more record field names)
- length of the index key expression
- length of the key.
EXAMPLE
This example obtains the index information from the .NDX file whose file descriptor is in "char *ndx" and prints this information on standard output.
#include "dbl.h" char *ndx; /* .NDX file descriptor */ char keytype; /* Key type */ char keyexpr[512]; /* Index key expression */ int keyexprlen; /* Expression length */ int keylen; /* Key length */ int rc; /* Return code */ rc = dbkexpr(ndx, &keytype, keyexpr, &keyexprlen, &keylen); if (rc == SUCCESS){ printf("\t Index file information - \n"); printf("\t \t type = '%c', keyexpression = '%s', exprlen = %d, keylen = %d \n". keytype, keyexpr, keyexprlen, keylen); } else { printf("error number %d \n", rc); exit (1); }
