Deletion of Pointers Issue

Question

I am having trouble deleting my pointers that I have created. The program creates a double pointer to point to the threads. Then it creates threads dynamically. At the end it deletes them but I am getting a glibc error. It uses boost to create the threads. What is really puzzling is that I delete a similar double pointer the same exact way and that executes fine. The issue is at the end of the code block under the heading of /*clean up*/:

boost :: thread** thrds;

//create threads and bind to p_variantforloop_t
thrds = new boost::thread*[numThreads];

for (int i = 1; i <= numThreads; i++)
    thrds[i] = new boost::thread(boost::bind(&p_variantforloop_t, 
        E, A, D, (i*n-n)/i ,(i*n)/n, numThreads, n)); 

/* join threads */
for (int i = 0; i < numThreads; i++)
    thrds[i]->join();

/* cleanup */
for (int i = 0; i < numThreads; i++)
    delete thrds[i];
delete[] thrds;

the error is:

*** glibc detected *** ./hw9: munmap_chunk(): invalid pointer: 0x0957d480 ***
======= Backtrace: =========
/lib/tls/i686/cmov/libc.so.6(+0x6b591)[0x264591]
/lib/tls/i686/cmov/libc.so.6(+0x6c80e)[0x26580e]
/usr/lib/libstdc++.so.6(_ZdlPv+0x21)[0x529741]
./hw9[0x804a0d1]
/lib/tls/i686/cmov/libc.so.6(__libc_start_main+0xe6)[0x20fbd6]
./hw9[0x8049871]
======= Memory map: ========
001f9000-0034c000 r-xp 00000000 08:02 1128663 /lib/tls/i686/cmov/libc-2.11.1.so
0034c000-0034d000 ---p 00153000 08:02 1128663 /lib/tls/i686/cmov/libc-2.11.1.so
0034d000-0034f000 r--p 00153000 08:02 1128663 /lib/tls/i686/cmov/libc-2.11.1.so
0034f000-00350000 rw-p 00155000 08:02 1128663 /lib/tls/i686/cmov/libc-2.11.1.so
00350000-00353000 rw-p 00000000 00:00 0
0046e000-00557000 r-xp 00000000 08:02 982712 /usr/lib/libstdc++.so.6.0.13
00557000-00558000 ---p 000e9000 08:02 982712 /usr/lib/libstdc++.so.6.0.13
00558000-0055c000 r--p 000e9000 08:02 982712 /usr/lib/libstdc++.so.6.0.13
0055c000-0055d000 rw-p 000ed000 08:02 982712 /usr/lib/libstdc++.so.6.0.13
0055d000-00564000 rw-p 00000000 00:00 0
005ad000-005d1000 r-xp 00000000 08:02 1130719 /lib/tls/i686/cmov/libm-2.11.1.so
005d1000-005d2000 r--p 00023000 08:02 1130719 /lib/tls/i686/cmov/libm-2.11.1.so
005d2000-005d3000 rw-p 00024000 08:02 1130719 /lib/tls/i686/cmov/libm-2.11.1.so
00950000-00965000 r-xp 00000000 08:02 1130743 /lib/tls/i686/cmov/libpthread-2.11.1.so
00965000-00966000 r--p 00014000 08:02 1130743 /lib/tls/i686/cmov/libpthread-2.11.1.so
00966000-00967000 rw-p 00015000 08:02 1130743 /lib/tls/i686/cmov/libpthread-2.11.1.so
00967000-00969000 rw-p 00000000 00:00 0
00a67000-00a7a000 r-xp 00000000 08:02 176445 /usr/lib/libboost_thread.so.1.40.0
00a7a000-00a7b000 r--p 00013000 08:02 176445 /usr/lib/libboost_thread.so.1.40.0
00a7b000-00a7c000 rw-p 00014000 08:02 176445 /usr/lib/libboost_thread.so.1.40.0
00bc7000-00be2000 r-xp 00000000 08:02 1128318 /lib/ld-2.11.1.so
00be2000-00be3000 r--p 0001a000 08:02 1128318 /lib/ld-2.11.1.so
00be3000-00be4000 rw-p 0001b000 08:02 1128318 /lib/ld-2.11.1.so
00c34000-00c3b000 r-xp 00000000 08:02 1130745 /lib/tls/i686/cmov/librt-2.11.1.so
00c3b000-00c3c000 r--p 00006000 08:02 1130745 /lib/tls/i686/cmov/librt-2.11.1.so
00c3c000-00c3d000 rw-p 00007000 08:02 1130745 /lib/tls/i686/cmov/librt-2.11.1.so
00ccf000-00cd0000 r-xp 00000000 00:00 0 [vdso]
00e85000-00ea2000 r-xp 00000000 08:02 1128359 /lib/libgcc_s.so.1
00ea2000-00ea3000 r--p 0001c000 08:02 1128359 /lib/libgcc_s.so.1
00ea3000-00ea4000 rw-p 0001d000 08:02 1128359 /lib/libgcc_s.so.1
08048000-0804e000 r-xp 00000000 00:1d 10184 /home/tparisi/Desktop/source_code_hw5/hw9
0804e000-0804f000 r--p 00005000 00:1d 10184 /home/tparisi/Desktop/source_code_hw5/hw9
0804f000-08050000 rw-p 00006000 00:1d 10184 /home/tparisi/Desktop/source_code_hw5/hw9
0957d000-0959e000 rw-p 00000000 00:00 0 [heap]
b68bf000-b68c0000 ---p 00000000 00:00 0
b68c0000-b70c0000 rw-p 00000000 00:00 0
b70c0000-b70c1000 ---p 00000000 00:00 0
b70c1000-b78c4000 rw-p 00000000 00:00 0
b78e8000-b78eb000 rw-p 00000000 00:00 0
bfc07000-bfc1c000 rw-p 00000000 00:00 0 [stack]
Aborted

Answer 1

You omit first element of the array when creating thread object. It stays with uninitialized pointer value, causing the invalid pointer error later.

There is also an issue of writing to memory immediately after the last element of array, which you also do in the problematic loop (i.e. the first for in your code).