Seg fault even though address space is accessible

[Ajay]

Hi All,

I got a segmentation fault while accessing a structure element.
I pasted the output from gdb and the backtrace.

However if I am able successfully access the structure using the
address from the gdb output
after it seg faulted. Output from gdb also give below.

Any idea y this is happening?
yes I am trying to access the structure element from where it seg
faulted.

I am surely missing something.
Any help is appreciated!

Thanks,
Ajay.

$$$$$$$$$$$$$ SEG FAULT $$$$$$$$$$$$$$$ $$

Program received signal SIGSEGV, Segmentation fault.
checkBFVectorLi st (BFVecList=0x84 187a0, BFlen=699)
at compute_sticky_ IP_per_ASN.c:77 6
776 vector = vector->nextVector;

$$$$$$$$$$$$$$$ $ BT $$$$$$$$$$$$$$$ $$$$$

(gdb) bt
#0 checkBFVectorLi st (BFVecList=0x84 187a0, BFlen=699)
at compute_sticky_ IP_per_ASN.c:77 6
#1 0x08051bb3 in buildPeerDetail StructFromLine (line=0x8418dd0 "566",
peerStruct=0x80 47124) at compute_sticky_ IP_per_ASN.c:75 2
#2 0x080522c1 in main (argc=11, argv=0x8047348)
at compute_sticky_ IP_per_ASN.c:17 9

$$$$$$$$$$$$$$$ $$$$$ ACCESSING STRUCTURE $$$$$$$$$$$$$$$ $$$$

(gdb) p *(bitfieldItemS truct *) 0x84187a0
$1 = {BFVector = 3309413121, nextVector = 0x84187b0}
(gdb) p ((bitfieldItemS truct *) 0x84187a0)->nextVector
$2 = (struct bitfieldItem *) 0x84187b0
(gdb) p ((struct bitfieldItem *) 0x84187a0)->nextVector
$3 = (struct bitfieldItem *) 0x84187b0

[user923005]

On Jul 29, 2:52*pm, Ajay <ajay.todim...@ gmail.comwrote:

Hi All,

I got a segmentation fault while accessing a structure element.
I pasted the output from gdb and the backtrace.

However if I am able successfully access the structure using the
address from the gdb output
after it seg faulted. Output from gdb also give below.

Any idea y this is happening?
yes I am trying to access the structure element from where it seg
faulted.

I am surely missing something.
Any help is appreciated!

Thanks,
Ajay.

$$$$$$$$$$$$$ SEG FAULT $$$$$$$$$$$$$$$ $$

Program received signal SIGSEGV, Segmentation fault.
checkBFVectorLi st (BFVecList=0x84 187a0, BFlen=699)
* * at compute_sticky_ IP_per_ASN.c:77 6
776 * * * * * * * * * * vector = vector->nextVector;

$$$$$$$$$$$$$$$ $ BT $$$$$$$$$$$$$$$ $$$$$

(gdb) bt
#0 *checkBFVectorL ist (BFVecList=0x84 187a0, BFlen=699)
* * at compute_sticky_ IP_per_ASN.c:77 6
#1 *0x08051bb3 in buildPeerDetail StructFromLine (line=0x8418dd0 "566",
* * peerStruct=0x80 47124) at compute_sticky_ IP_per_ASN.c:75 2
#2 *0x080522c1 in main (argc=11, argv=0x8047348)
* * at compute_sticky_ IP_per_ASN.c:17 9

$$$$$$$$$$$$$$$ $$$$$ ACCESSING STRUCTURE $$$$$$$$$$$$$$$ $$$$

(gdb) p *(bitfieldItemS truct *) 0x84187a0
$1 = {BFVector = 3309413121, nextVector = 0x84187b0}
(gdb) p ((bitfieldItemS truct *) 0x84187a0)->nextVector
$2 = (struct bitfieldItem *) 0x84187b0
(gdb) p ((struct bitfieldItem *) 0x84187a0)->nextVector
$3 = (struct bitfieldItem *) 0x84187b0

Maybe an alignment problem.
Did you try the GNU groups?
http://www.nabble.com/Gnu---gdb-f1618.html
news:gnu.gdb.bu g

[Ajay]

On Jul 29, 6:01*pm, user923005 <dcor...@connx. comwrote:

On Jul 29, 2:52*pm, Ajay <ajay.todim...@ gmail.comwrote:

Hi All,

I got a segmentation fault while accessing a structure element.
I pasted the output from gdb and the backtrace.

However if I am able successfully access the structure using the
address from the gdb output
after it seg faulted. Output from gdb also give below.

Any idea y this is happening?
yes I am trying to access the structure element from where it seg
faulted.

I am surely missing something.
Any help is appreciated!

Thanks,
Ajay.

$$$$$$$$$$$$$ SEG FAULT $$$$$$$$$$$$$$$ $$

Program received signal SIGSEGV, Segmentation fault.
checkBFVectorLi st (BFVecList=0x84 187a0, BFlen=699)
* * at compute_sticky_ IP_per_ASN.c:77 6
776 * * * * * * * * * * vector = vector->nextVector;

$$$$$$$$$$$$$$$ $ BT $$$$$$$$$$$$$$$ $$$$$

(gdb) bt
#0 *checkBFVectorL ist (BFVecList=0x84 187a0, BFlen=699)
* * at compute_sticky_ IP_per_ASN.c:77 6
#1 *0x08051bb3 in buildPeerDetail StructFromLine (line=0x8418dd0 "566",
* * peerStruct=0x80 47124) at compute_sticky_ IP_per_ASN.c:75 2
#2 *0x080522c1 in main (argc=11, argv=0x8047348)
* * at compute_sticky_ IP_per_ASN.c:17 9

$$$$$$$$$$$$$$$ $$$$$ ACCESSING STRUCTURE $$$$$$$$$$$$$$$ $$$$

(gdb) p *(bitfieldItemS truct *) 0x84187a0
$1 = {BFVector = 3309413121, nextVector = 0x84187b0}
(gdb) p ((bitfieldItemS truct *) 0x84187a0)->nextVector
$2 = (struct bitfieldItem *) 0x84187b0
(gdb) p ((struct bitfieldItem *) 0x84187a0)->nextVector
$3 = (struct bitfieldItem *) 0x84187b0

Maybe an alignment problem.
Did you try the GNU groups?http://www.nabble.com/Gnu---gdb-f1618.html
news:gnu.gdb.bu g

Hmmm! I haven't, Let me try that.
But, how can I find if its an alignment problem?

However, I checked the address space which are function parameters.
And it appears it is aligned. :(

-Ajay.

[Ben Bacarisse]

Ajay <aj***********@ gmail.comwrites :

I got a segmentation fault while accessing a structure element.
I pasted the output from gdb and the backtrace.

The usual advice is to post code. Ideally code you have cut right
down but which still exhibits the problem. Doing this often isolates
the issue anyway, but without code to see it is tough...

However if I am able successfully access the structure using the
address from the gdb output
after it seg faulted. Output from gdb also give below.

Any idea y this is happening?
yes I am trying to access the structure element from where it seg
faulted.

I am surely missing something.
Any help is appreciated!

Thanks,
Ajay.

$$$$$$$$$$$$$ SEG FAULT $$$$$$$$$$$$$$$ $$

Program received signal SIGSEGV, Segmentation fault.
checkBFVectorLi st (BFVecList=0x84 187a0, BFlen=699)
at compute_sticky_ IP_per_ASN.c:77 6
776 vector = vector->nextVector;

$$$$$$$$$$$$$$$ $ BT $$$$$$$$$$$$$$$ $$$$$

(gdb) bt
#0 checkBFVectorLi st (BFVecList=0x84 187a0, BFlen=699)
at compute_sticky_ IP_per_ASN.c:77 6
#1 0x08051bb3 in buildPeerDetail StructFromLine (line=0x8418dd0 "566",
peerStruct=0x80 47124) at compute_sticky_ IP_per_ASN.c:75 2
#2 0x080522c1 in main (argc=11, argv=0x8047348)
at compute_sticky_ IP_per_ASN.c:17 9

$$$$$$$$$$$$$$$ $$$$$ ACCESSING STRUCTURE $$$$$$$$$$$$$$$ $$$$

(gdb) p *(bitfieldItemS truct *) 0x84187a0
$1 = {BFVector = 3309413121, nextVector = 0x84187b0}
(gdb) p ((bitfieldItemS truct *) 0x84187a0)->nextVector
$2 = (struct bitfieldItem *) 0x84187b0
(gdb) p ((struct bitfieldItem *) 0x84187a0)->nextVector
$3 = (struct bitfieldItem *) 0x84187b0

To me, this does not show anything interesting. The fault is with
'vector' not 'BFVecList' which is the only thing that has the value
0x84187a0 (as far as I can see). Did you miss out the 'print vector'
output showing it to be equal to 'BFVecList'? Why not just try to
print vector->nextVector rather than using some mysterious (to me)
address?

--
Ben.

[Richard Heathfield]

Ajay said:

Hi All,

I got a segmentation fault while accessing a structure element.
I pasted the output from gdb and the backtrace.

There's a guy around here somewhere who can debug your problem (no matter
what it is) using only the debugger. Impressive. But if by some strange
chance he doesn't have time to answer your question, you'll have to rely
on the rest of us, and I'm afraid we tend to need to see the source code.

Without it, the most I can suggest is that you may have violated the bounds
of your array. The fact that gdb lets you look at an address outside the
array doesn't mean anything with regard to your program's correctness.

<snip>

--
Richard Heathfield <http://www.cpax.org.uk >
Email: -http://www. +rjh@
Google users: <http://www.cpax.org.uk/prg/writings/googly.php>
"Usenet is a strange place" - dmr 29 July 1999

[Jens Thoms Toerring]

Ajay <aj***********@ gmail.comwrote:

I got a segmentation fault while accessing a structure element.
I pasted the output from gdb and the backtrace.

Wich is rather useless without seeing the code. Without it the
gdb output is mostly meaningless.

However if I am able successfully access the structure using the
address from the gdb output
after it seg faulted. Output from gdb also give below.

$$$$$$$$$$$$$ SEG FAULT $$$$$$$$$$$$$$$ $$

Program received signal SIGSEGV, Segmentation fault.
checkBFVectorLi st (BFVecList=0x84 187a0, BFlen=699)
at compute_sticky_ IP_per_ASN.c:77 6
776 vector = vector->nextVector;

What value has 'vector here? Did you check that it's an
address you can legally use as a pointer? Without seeing
your code there's nothing that indicates that 'vector'
has anything to do with the address 0x84187a0.

$$$$$$$$$$$$$$$ $ BT $$$$$$$$$$$$$$$ $$$$$

(gdb) bt
#0 checkBFVectorLi st (BFVecList=0x84 187a0, BFlen=699)
at compute_sticky_ IP_per_ASN.c:77 6
#1 0x08051bb3 in buildPeerDetail StructFromLine (line=0x8418dd0 "566",
peerStruct=0x80 47124) at compute_sticky_ IP_per_ASN.c:75 2
#2 0x080522c1 in main (argc=11, argv=0x8047348)
at compute_sticky_ IP_per_ASN.c:17 9

$$$$$$$$$$$$$$$ $$$$$ ACCESSING STRUCTURE $$$$$$$$$$$$$$$ $$$$

(gdb) p *(bitfieldItemS truct *) 0x84187a0
$1 = {BFVector = 3309413121, nextVector = 0x84187b0}
(gdb) p ((bitfieldItemS truct *) 0x84187a0)->nextVector
$2 = (struct bitfieldItem *) 0x84187b0
(gdb) p ((struct bitfieldItem *) 0x84187a0)->nextVector

I don't understand what you're doing here. Doing

p ((bitfieldItemS truct *) 0x84187a0)->nextVector
p ((struct bitfieldItem *) 0x84187a0)->nextVector

looks suspicious. Note that you use the same address in
both cases, just casting it to a different type - or is
it the same? If yes, why do you think it's relevant to
check the same thing twice?

Regards, Jens
--
\ Jens Thoms Toerring ___ [e-mail]
\______________ ____________ http://toerring.de

[Ajay]

Hi All,

Thanks for all your replays.

I am posting the code here.
typedef struct bitfieldItem {
uint32_t BFVector;
const struct bitfieldItem *nextVector;
} bitfieldItemStr uct, *bitfieldItemSt ructPtr;

main()
{
***
buildBFVectorLi st(currPeerDeta ilItem->bitfieldStr,
&(currPeerDetai lItem->bitfieldVector ));
checkBFVectorLi st(currPeerDeta ilItem->bitfieldVector ,
currPeerDetailI tem->bitfieldLength );

***

}
int checkBFVectorLi st(bitfieldItem Struct **BFVecList, unsigned int
BFlen)
{
bitfieldItemStr uct *vector = *BFVecList;
float numVectors = ceil((float)BFl en/32.0);
float vector_id = 0;
printf ("Verifying BF vector\n");
printf ("BFlen = %d, numvectors = %f\n", BFlen, numVectors);
printf ("The BF vector is: ");
while (vector != NULL)
{
printf ("%d ", vector->BFVector);
vector = vector->nextVector;
vector_id++;
}
printf ("\nvector_i d = %d\n", vector_id);
assert (vector_id == numVectors);
return 1;
}

int
buildBFVectorLi st(char *BFStr, bitfieldItemStr uct **BFVecList)
{
bitfieldItemStr uct *BFVecHead, *currBFVec, *tmpBFVec;
char * bit;
unsigned int num_bits_pushed = 0;
unsigned int total_num_bits_ pushed = 0;
unsigned int num_vectors = 0;

if (verboseLevel >= 7) printf ("The BF string is %s\n", BFStr);
bit = (char *) strtok(BFStr, ",");
BFVecHead = (bitfieldItemSt ruct *) calloc(1,
sizeof(bitfield ItemStruct *));
BFVecHead->BFVector = 0;
BFVecHead->nextVector = NULL;
currBFVec = BFVecHead;
num_vectors = 1;
printf ("Before %u\n", BFVecHead->BFVector);

while (bit != NULL)
{
if (verboseLevel >= 9) printf ("%d: Current bit is %s\n",
total_num_bits_ pushed+1, bit);
if (num_bits_pushe d >= 32) {
printf ("\nAfter %u\n", currBFVec->BFVector);
if (tmpBFVec = (bitfieldItemSt ruct *) calloc(1,
sizeof(bitfield ItemStruct *)) == NULL) {
printf ("Memory reallocation failed for object of type
'bitfieldItemSt ruct*'.\n");
exit(-1);
}
tmpBFVec->BFVector= 0;
tmpBFVec->nextVector = NULL;
currBFVec->nextVector = tmpBFVec;
currBFVec = tmpBFVec;
num_bits_pushed = 0;
num_vectors++;
printf ("Before %u\n", currBFVec->BFVector);
}

currBFVec->BFVector = currBFVec->BFVector << 1;
printf ("%u", atoi(bit));
currBFVec->BFVector += atoi(bit);
num_bits_pushed ++;
total_num_bits_ pushed++;
bit = (char *) strtok(NULL, ",");
}
printf ("\nAfter %u\n", currBFVec->BFVector);
*BFVecList = BFVecHead;
printf ("The total number of bits in the BFvector is %d and num
vectors is %d.\n", total_num_bits_ pushed, num_vectors);
return 1;
}

On Jul 29, 6:18*pm, Ben Bacarisse <ben.use...@bsb .me.ukwrote:

Ajay <ajay.todim...@ gmail.comwrites :

I got a segmentation fault while accessing a structure element.
I pasted the output from gdb and the backtrace.

The usual advice is to post code. *Ideally code you have cut right
down but which still exhibits the problem. *Doing this often isolates
the issue anyway, but without code to see it is tough...

However if I am able successfully access the structure using the
address from the gdb output
after it seg faulted. Output from gdb also give below.

Any idea y this is happening?
yes I am trying to access the structure element from where it seg
faulted.

I am surely missing something.
Any help is appreciated!

Thanks,
Ajay.

$$$$$$$$$$$$$ SEG FAULT $$$$$$$$$$$$$$$ $$

Program received signal SIGSEGV, Segmentation fault.
checkBFVectorLi st (BFVecList=0x84 187a0, BFlen=699)
* * at compute_sticky_ IP_per_ASN.c:77 6
776 * * * * * * * * * * vector = vector->nextVector;

$$$$$$$$$$$$$$$ $ BT $$$$$$$$$$$$$$$ $$$$$

(gdb) bt
#0 *checkBFVectorL ist (BFVecList=0x84 187a0, BFlen=699)
* * at compute_sticky_ IP_per_ASN.c:77 6
#1 *0x08051bb3 in buildPeerDetail StructFromLine (line=0x8418dd0 "566",
* * peerStruct=0x80 47124) at compute_sticky_ IP_per_ASN.c:75 2
#2 *0x080522c1 in main (argc=11, argv=0x8047348)
* * at compute_sticky_ IP_per_ASN.c:17 9

$$$$$$$$$$$$$$$ $$$$$ ACCESSING STRUCTURE $$$$$$$$$$$$$$$ $$$$

(gdb) p *(bitfieldItemS truct *) 0x84187a0
$1 = {BFVector = 3309413121, nextVector = 0x84187b0}
(gdb) p ((bitfieldItemS truct *) 0x84187a0)->nextVector
$2 = (struct bitfieldItem *) 0x84187b0
(gdb) p ((struct bitfieldItem *) 0x84187a0)->nextVector
$3 = (struct bitfieldItem *) 0x84187b0

To me, this does not show anything interesting. *The fault is with
'vector' not 'BFVecList' which is the only thing that has the value
0x84187a0 (as far as I can see). *Did you miss out the 'print vector'
output showing it to be equal to 'BFVecList'? *Why not just try to
print vector->nextVector rather than using some mysterious (to me)
address?

--
Ben.

[Ben Bacarisse]

Ajay <aj***********@ gmail.comwrites :

I am posting the code here.

Makes all the difference... BTW, top-posting is not in favour in the
group.

typedef struct bitfieldItem {
uint32_t BFVector;
const struct bitfieldItem *nextVector;
} bitfieldItemStr uct, *bitfieldItemSt ructPtr;

<snip>

int
buildBFVectorLi st(char *BFStr, bitfieldItemStr uct **BFVecList)
{
bitfieldItemStr uct *BFVecHead, *currBFVec, *tmpBFVec;
char * bit;
unsigned int num_bits_pushed = 0;
unsigned int total_num_bits_ pushed = 0;
unsigned int num_vectors = 0;

if (verboseLevel >= 7) printf ("The BF string is %s\n", BFStr);
bit = (char *) strtok(BFStr, ",");
BFVecHead = (bitfieldItemSt ruct *) calloc(1,
sizeof(bitfield ItemStruct *));

This is wrong. There is no need for calloc (you set the memory
immediately), the cast is unnecessary, and you don't check the result.
However, the reason things go really wrong is the size is not right.

The comp.lang.c approved method is to write:

BFVecHead = malloc(sizeof *BFVecHead);

This way you can see the size is right (provided the type of the
pointer is correct) and you will get an error message if you have
forgotten to include stdlib.h.

BFVecHead->BFVector = 0;
BFVecHead->nextVector = NULL;
currBFVec = BFVecHead;
num_vectors = 1;
printf ("Before %u\n", BFVecHead->BFVector);

while (bit != NULL)
{
if (verboseLevel >= 9) printf ("%d: Current bit is %s\n",
total_num_bits_ pushed+1, bit);
if (num_bits_pushe d >= 32) {
printf ("\nAfter %u\n", currBFVec->BFVector);
if (tmpBFVec = (bitfieldItemSt ruct *) calloc(1,
sizeof(bitfield ItemStruct *)) == NULL) {

Ditto.

printf ("Memory reallocation failed for object of type
'bitfieldItemSt ruct*'.\n");
exit(-1);
}
tmpBFVec->BFVector= 0;
tmpBFVec->nextVector = NULL;
currBFVec->nextVector = tmpBFVec;
currBFVec = tmpBFVec;
num_bits_pushed = 0;
num_vectors++;
printf ("Before %u\n", currBFVec->BFVector);
}

currBFVec->BFVector = currBFVec->BFVector << 1;
printf ("%u", atoi(bit));
currBFVec->BFVector += atoi(bit);
num_bits_pushed ++;
total_num_bits_ pushed++;
bit = (char *) strtok(NULL, ",");
}
printf ("\nAfter %u\n", currBFVec->BFVector);
*BFVecList = BFVecHead;
printf ("The total number of bits in the BFvector is %d and num
vectors is %d.\n", total_num_bits_ pushed, num_vectors);
return 1;
}

--
Ben.

[Ajay]

On Jul 29, 7:25*pm, Ben Bacarisse <ben.use...@bsb .me.ukwrote:

Ajay <ajay.todim...@ gmail.comwrites :

I am posting the code here.

Makes all the difference... *BTW, top-posting is not in favour in the
group.

typedef struct bitfieldItem {
* * uint32_t * *BFVector;
* * const struct bitfieldItem *nextVector;
} bitfieldItemStr uct, *bitfieldItemSt ructPtr;

<snip>

int
buildBFVectorLi st(char *BFStr, bitfieldItemStr uct **BFVecList)
{
* * bitfieldItemStr uct *BFVecHead, *currBFVec, *tmpBFVec;
* * char * bit;
* * unsigned int num_bits_pushed = 0;
* * unsigned int total_num_bits_ pushed = 0;
* * unsigned int num_vectors = 0;

* * if (verboseLevel >= 7) printf ("The BF string is %s\n", BFStr);
* * bit = (char *) strtok(BFStr, ",");
* * BFVecHead = (bitfieldItemSt ruct *) calloc(1,
sizeof(bitfield ItemStruct *));

This is wrong. *There is no need for calloc (you set the memory
immediately), the cast is unnecessary, and you don't check the result.
However, the reason things go really wrong is the size is not right.

The comp.lang.c approved method is to write:

* * BFVecHead = malloc(sizeof *BFVecHead);

This way you can see the size is right (provided the type of the
pointer is correct) and you will get an error message if you have
forgotten to include stdlib.h.

* * BFVecHead->BFVector = 0;
* * BFVecHead->nextVector = NULL;
* * currBFVec = BFVecHead;
* * num_vectors = 1;
* * printf ("Before %u\n", BFVecHead->BFVector);

* * while (bit != NULL)
* * {
* * * * if (verboseLevel >= 9) printf ("%d: Current bit is %s\n",
total_num_bits_ pushed+1, bit);
* * * * if (num_bits_pushe d >= 32) {
* * * * * * printf ("\nAfter %u\n", currBFVec->BFVector);
* * * * * * if (tmpBFVec = (bitfieldItemSt ruct *) calloc(1,
sizeof(bitfield ItemStruct *)) == NULL) {

Ditto.

* * * * * * * * printf ("Memory reallocation failed forobject of type
'bitfieldItemSt ruct*'.\n");
* * * * * * * * exit(-1);
* * * * * * }
* * * * * * tmpBFVec->BFVector= 0;
* * * * * * tmpBFVec->nextVector = NULL;
* * * * * * currBFVec->nextVector = tmpBFVec;
* * * * * * currBFVec = tmpBFVec;
* * * * * * num_bits_pushed = 0;
* * * * * * num_vectors++;
* * * * * * printf ("Before %u\n", currBFVec->BFVector);
* * * * }

* * * * currBFVec->BFVector = currBFVec->BFVector << 1;
* * * * printf ("%u", atoi(bit));
* * * * currBFVec->BFVector += atoi(bit);
* * * * num_bits_pushed ++;
* * * * total_num_bits_ pushed++;
* * * * bit = (char *) strtok(NULL, ",");
* * }
* * printf ("\nAfter %u\n", currBFVec->BFVector);
* * *BFVecList = BFVecHead;
* * printf ("The total number of bits in the BFvector is %d and num
vectors is %d.\n", total_num_bits_ pushed, num_vectors);
* * return 1;
}

--
Ben.

Hi Ben,

Thanks for your replay!
I was using malloc but after the error appeared, I tried using calloc.
I changed back the code to using malloc.
The Seg. fault error still persists.
The new code is posted below:

Thanks,
Ajay.

int
checkBFVectorLi st(bitfieldItem Struct **BFVecList, unsigned int BFlen)
{
bitfieldItemStr uct *vector = *BFVecList;
float numVectors = ceil((float)BFl en/32.0);
float vector_id = 0;
printf ("Verifying BF vector\n");
printf ("BFlen = %d, numvectors = %f\n", BFlen, numVectors);
printf ("The BF vector is: ");
while (vector != NULL)
{
/* if (vector->BFVector != NULL) printf ("%u ", vector-

>BFVector);

else { printf ("Error occured\n"); exit(-1); } */
/* printf ("%d ", vector->BFVector);*/
vector = vector->nextVector;
vector_id++;
}
printf ("\nvector_i d = %d\n", vector_id);
assert (vector_id == numVectors);
return 1;
}

int
buildBFVectorLi st(char *BFStr, bitfieldItemStr uct **BFVecList)
{
bitfieldItemStr uct *BFVecHead, *currBFVec, *tmpBFVec;
char * bit;
unsigned int num_bits_pushed = 0;
unsigned int total_num_bits_ pushed = 0;
unsigned int num_vectors = 0;

if (verboseLevel >= 7) printf ("The BF string is %s\n", BFStr);
bit = (char *) strtok(BFStr, ",");
BFVecHead = malloc(sizeof(* BFVecHead));
if (BFVecHead == NULL) {
perror("Error: Memory could not be allocated:");
exit(-1);
}
BFVecHead->BFVector = 0;
BFVecHead->nextVector = NULL;
currBFVec = BFVecHead;
num_vectors = 1;
printf ("Before %u\n", BFVecHead->BFVector);

while (bit != NULL)
{
if (verboseLevel >= 9) printf ("%d: Current bit is %s\n",
total_num_bits_ pushed+1, bit);
if (num_bits_pushe d >= 32) {
printf ("\nAfter %u\n", currBFVec->BFVector);
tmpBFVec = malloc(sizeof(* tmpBFVec));
if (tmpBFVec == NULL) {
perror("Error: Memory could not be allocated:");
exit(-1);
}
tmpBFVec->BFVector= 0;
tmpBFVec->nextVector = NULL;
currBFVec->nextVector = tmpBFVec;
currBFVec = tmpBFVec;
num_bits_pushed = 0;
num_vectors++;
printf ("Before %u\n", currBFVec->BFVector);
}

currBFVec->BFVector = currBFVec->BFVector << 1;
printf ("%u", atoi(bit));
currBFVec->BFVector += atoi(bit);
num_bits_pushed ++;
total_num_bits_ pushed++;
bit = (char *) strtok(NULL, ",");
}
printf ("\nAfter %u\n", currBFVec->BFVector);
*BFVecList = BFVecHead;
printf ("The total number of bits in the BFvector is %d and num
vectors is %d.\n", total_num_bits_ pushed, num_vectors);
return 1;
}

[Ben Bacarisse]

Ajay <aj***********@ gmail.comwrites :

Thanks for your replay!
I was using malloc but after the error appeared, I tried using calloc.
I changed back the code to using malloc.
The Seg. fault error still persists.
The new code is posted below:

Are you sure you are posting code you have compiled?

int
checkBFVectorLi st(bitfieldItem Struct **BFVecList, unsigned int BFlen)

int
buildBFVectorLi st(char *BFStr, bitfieldItemStr uct **BFVecList)

elsewhere you posted:

| main()
| {
| ***
| buildBFVectorLi st(currPeerDeta ilItem->bitfieldStr,
| &(currPeerDetai lItem->bitfieldVector ));
| checkBFVectorLi st(currPeerDeta ilItem->bitfieldVector ,
| currPeerDetailI tem->bitfieldLength );
|
| ***
|
| }

The types here do not match up -- the compiler should reject it.

--
Ben.