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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)
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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)
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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)
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