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009lin

Member

Registered: 2007-08-17

Posts: 2

can's compile the gdbm program ?(SOLVED)

Here is an example comes from Beginning Linux Programming 3rd ,and I can't compile it on my machine. I don't know why?? And the gdbm package is always in the base. Please help me.

try compile 1：
$gcc dbm1.c -o gdbm1 -lgdbm
错误信息：
/tmp/cc2vMknU.o: In function `main':
dbm1.c: (.text+0x2d): undefined reference to `dbm_open'
dbm1.c: (.text+0x244): undefined reference to `dbm_store'
dbm1.c: (.text+0x2ee): undefined reference to `dbm_fetch'
dbm1.c: (.text+0x379): undefined reference to `dbm_close'
collect2: ld returned 1 exit status

try compile 2：
$ gcc dbm1.c -o gdbm1 -lndbm -L/usr/lib
错误信息：
/usr/bin/ld: cannot find -lndbm
collect2: ld returned 1 exit status

#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <fcntl.h>
#include <ndbm.h>
#include <string.h>

#define TEST_DB_FILE "/tmp/dbm1_test"
#define ITEMS_USED 3

/* A struct to use to test dbm */
struct test_data {
    char misc_chars[15];
    int  any_integer;
    char more_chars[21];
};

int main() {

    struct test_data items_to_store[ITEMS_USED];
    struct test_data item_retrieved;

    char key_to_use[20];
    int i, result;

    datum key_datum;
    datum data_datum;

    DBM *dbm_ptr;

    dbm_ptr = dbm_open(TEST_DB_FILE, O_RDWR | O_CREAT, 0666);
    if (!dbm_ptr) {
        fprintf(stderr, "Failed to open database\n");
        exit(EXIT_FAILURE);
    }

        /* put some data in the structures */
    memset(items_to_store, '\0', sizeof(items_to_store));
    strcpy(items_to_store[0].misc_chars, "First!");
    items_to_store[0].any_integer = 47;
    strcpy(items_to_store[0].more_chars, "foo");
    strcpy(items_to_store[1].misc_chars, "bar");
    items_to_store[1].any_integer = 13;
    strcpy(items_to_store[1].more_chars, "unlucky?");
    strcpy(items_to_store[2].misc_chars, "Third");
    items_to_store[2].any_integer = 3;
    strcpy(items_to_store[2].more_chars, "baz");

    for (i = 0; i < ITEMS_USED; i++) {
            /* build a key to use */
        sprintf(key_to_use, "%c%c%d",
            items_to_store[i].misc_chars[0],
            items_to_store[i].more_chars[0],
            items_to_store[i].any_integer);

            /* build the key datum strcture */
        key_datum.dptr = (void *)key_to_use;
        key_datum.dsize = strlen(key_to_use);
        data_datum.dptr = (void *)&items_to_store[i];
        data_datum.dsize = sizeof(struct test_data);

        result = dbm_store(dbm_ptr, key_datum, data_datum, DBM_REPLACE);
        if (result != 0) {
            fprintf(stderr, "dbm_store failed on key %s\n", key_to_use);
            exit(2);
        }
    } /* for */

        /* now try and retrieve some data */
    sprintf(key_to_use, "bu%d", 13); /* this is the key for the second item */
    key_datum.dptr = key_to_use;
    key_datum.dsize = strlen(key_to_use);

    data_datum = dbm_fetch(dbm_ptr, key_datum);
    if (data_datum.dptr) {
        printf("Data retrieved\n");
        memcpy(&item_retrieved, data_datum.dptr, data_datum.dsize);
        printf("Retrieved item - %s %d %s\n",
               item_retrieved.misc_chars,
               item_retrieved.any_integer,
               item_retrieved.more_chars);
    }
    else {
        printf("No data found for key %s\n", key_to_use);
    }

    dbm_close(dbm_ptr);

    exit(EXIT_SUCCESS);
}

Last edited by 009lin (2007-08-19 02:29:54)

bboozzoo

Member

From: Poland

Registered: 2006-08-01

Posts: 125

Re: can's compile the gdbm program ?(SOLVED)

as far as I remember gdbm did provide some compatibility API for ndbm. You can always switch to gdbm specific API (then change DBM * to GDBM_FILE, #include <gdbm.h> and -lgdbm) or use Berkeley DB (#include <db.h>, and -ldb)

009lin

Member

Registered: 2007-08-17

Posts: 2

Re: can's compile the gdbm program ?(SOLVED)

GDBM includes dbm and ndbm compatability.

I found the solution from the man page, it said:

If you wish to use the dbm or ndbm  compatibility  routines,  you  must
       link in the gdbm_compat library as well.  For example:

            gcc -o prog proc.c -lgdbm -lgdbm_compat

Last edited by 009lin (2007-08-19 02:29:27)