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Asked: 2026-06-02T21:03:10+00:00

The next code uses igraph_neighborhood, and it runs good, i don’t know why i

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The next code uses igraph_neighborhood, and it runs good, i don’t know why i get 

#include <igraph.h>
#include <fstream>
#include <iostream>
#include <stdlib.h>
#include <vector>
#include <algorithm>



void print_vector(igraph_vector_t *v, FILE *f) {
  long int i;
  for (i=0; i<igraph_vector_size(v); i++) {
    fprintf(f, " %li", (long int) VECTOR(*v)[i]);
  }
  fprintf(f, "\n");
}

using namespace std;

int main() {

  igraph_t g;
  igraph_vector_t v;


  igraph_vector_init(&v,32);
  VECTOR(v)[0]=0; VECTOR(v)[1]=1;
  VECTOR(v)[2]=0; VECTOR(v)[3]=4;
  VECTOR(v)[4]=0; VECTOR(v)[5]=9;
  VECTOR(v)[6]=1; VECTOR(v)[7]=7;
  VECTOR(v)[8]=1; VECTOR(v)[9]=9;
  VECTOR(v)[10]=2; VECTOR(v)[11]=9;
  VECTOR(v)[12]=2; VECTOR(v)[13]=3;
  VECTOR(v)[14]=2; VECTOR(v)[15]=5;
  VECTOR(v)[16]=3; VECTOR(v)[17]=6;
  VECTOR(v)[18]=3; VECTOR(v)[19]=9;
  VECTOR(v)[20]=4; VECTOR(v)[21]=5;
  VECTOR(v)[22]=4; VECTOR(v)[23]=8;
  VECTOR(v)[24]=5; VECTOR(v)[25]=8;
  VECTOR(v)[26]=6; VECTOR(v)[27]=7;
  VECTOR(v)[28]=6; VECTOR(v)[29]=8;
  VECTOR(v)[30]=7; VECTOR(v)[31]=8;

  igraph_create(&g, &v, 0,0);

  // Cycle 1
  igraph_vector_ptr_t vn1;
  igraph_vs_t vs;
  long int i;

  igraph_vector_ptr_init(&vn1, 10);
  for (i=0; i<igraph_vector_ptr_size(&vn1); i++) {
    VECTOR(vn1)[i] = calloc(1, sizeof(igraph_vector_t));
    igraph_vector_init((igraph_vector_t *)VECTOR(vn1)[i], 0);
  }

  igraph_vs_vector_small(&vs, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, -1);
  igraph_neighborhood(&g, &vn1,vs, 1, IGRAPH_OUT);

  for (i=0; i<igraph_vector_ptr_size(&vn1); i++) {
    print_vector((igraph_vector_t *)VECTOR(vn1)[i],stdout);
    igraph_vector_destroy((igraph_vector_t *)VECTOR(vn1)[i]);
    free((igraph_vector_t *)VECTOR(vn1)[i]);
  } 

  igraph_vector_ptr_destroy(&vn1);
  igraph_vs_destroy(&vs);
  igraph_destroy(&g);

  if (!IGRAPH_FINALLY_STACK_EMPTY) return 1;

  return 0;
}

it runs good, but i have the next output Valgrind:
it runs good, but i have the next output Valgrind:
it runs good, but i have the next output Valgrind:

 ==13517== Memcheck, a memory error detector
==13517== Copyright (C) 2002-2009, and GNU GPL'd, by Julian Seward et al.
==13517== Using Valgrind-3.6.0.SVN-Debian and LibVEX; rerun with -h for copyright info
==13517== Command: ./example
==13517== 
--13517-- Valgrind options:
--13517--    --suppressions=/usr/lib/valgrind/debian-libc6-dbg.supp
--13517--    --leak-check=full
--13517--    -v
--13517-- Contents of /proc/version:
--13517--   Linux version 2.6.32-35-generic-pae (buildd@vernadsky) (gcc version 4.4.3 (Ubuntu 4.4.3-4ubuntu5) ) #78-Ubuntu SMP Tue Oct 11 17:01:12 UTC 2011
--13517-- Arch and hwcaps: X86, x86-sse1-sse2
--13517-- Page sizes: currently 4096, max supported 4096
--13517-- Valgrind library directory: /usr/lib/valgrind
--13517-- Reading syms from /lib/ld-2.11.1.so (0x4000000)
--13517-- Reading debug info from /lib/ld-2.11.1.so ..
--13517-- .. CRC mismatch (computed 45f50ae1 wanted 137bc614)
--13517-- Reading debug info from /usr/lib/debug/lib/ld-2.11.1.so ..
--13517-- Reading syms from /home/rvaca/workSpalceIgraphCpp/proyIgraph/example (0x8048000)
--13517-- Reading syms from /usr/lib/valgrind/memcheck-x86-linux (0x38000000)
--13517--    object doesn't have a dynamic symbol table
--13517-- Reading suppressions file: /usr/lib/valgrind/debian-libc6-dbg.supp
--13517-- Reading suppressions file: /usr/lib/valgrind/default.supp
--13517-- REDIR: 0x40160b0 (index) redirected to 0x3803e9b3 (vgPlain_x86_linux_REDIR_FOR_index)
--13517-- Reading syms from /usr/lib/valgrind/vgpreload_core-x86-linux.so (0x401f000)
--13517-- Reading syms from /usr/lib/valgrind/vgpreload_memcheck-x86-linux.so (0x4022000)
==13517== WARNING: new redirection conflicts with existing -- ignoring it
--13517--     new: 0x040160b0 (index               ) R-> 0x04025c30 index
--13517-- REDIR: 0x4016290 (strlen) redirected to 0x4026070 (strlen)
--13517-- Reading syms from /usr/local/lib/libigraph.so.0.0.0 (0x402b000)
--13517-- Reading syms from /usr/lib/libstdc++.so.6.0.13 (0x4213000)
--13517--    object doesn't have a symbol table
--13517-- Reading syms from /lib/tls/i686/cmov/libm-2.11.1.so (0x4308000)
--13517-- Reading debug info from /lib/tls/i686/cmov/libm-2.11.1.so ..
--13517-- .. CRC mismatch (computed a765a73c wanted 8d13be57)
--13517-- Reading debug info from /usr/lib/debug/lib/tls/i686/cmov/libm-2.11.1.so ..
--13517-- Reading syms from /lib/libgcc_s.so.1 (0x432e000)
--13517-- Reading debug info from /lib/libgcc_s.so.1 ..
--13517-- .. CRC mismatch (computed 338494ad wanted b1d69d39)
--13517--    object doesn't have a symbol table
--13517-- Reading syms from /lib/tls/i686/cmov/libc-2.11.1.so (0x434d000)
--13517-- Reading debug info from /lib/tls/i686/cmov/libc-2.11.1.so ..
--13517-- .. CRC mismatch (computed 2236eb0a wanted a071c0c3)
--13517-- Reading debug info from /usr/lib/debug/lib/tls/i686/cmov/libc-2.11.1.so ..
--13517-- Reading syms from /usr/lib/libxml2.so.2.7.6 (0x44a8000)
--13517-- Reading debug info from /usr/lib/libxml2.so.2.7.6 ..
--13517-- .. CRC mismatch (computed 8c0a5cb7 wanted d9f96831)
--13517--    object doesn't have a symbol table
--13517-- Reading syms from /usr/lib/libgmp.so.3.5.2 (0x45d3000)
--13517-- Reading debug info from /usr/lib/libgmp.so.3.5.2 ..
--13517-- .. CRC mismatch (computed b9cf7786 wanted 4db0a849)
--13517--    object doesn't have a symbol table
--13517-- Reading syms from /lib/tls/i686/cmov/libdl-2.11.1.so (0x4634000)
--13517-- Reading debug info from /lib/tls/i686/cmov/libdl-2.11.1.so ..
--13517-- .. CRC mismatch (computed 10f03463 wanted f15a6db6)
--13517-- Reading debug info from /usr/lib/debug/lib/tls/i686/cmov/libdl-2.11.1.so ..
--13517-- Reading syms from /lib/libz.so.1.2.3.3 (0x4638000)
--13517-- Reading debug info from /lib/libz.so.1.2.3.3 ..
--13517-- .. CRC mismatch (computed 53909dc3 wanted dc0e37c9)
--13517--    object doesn't have a symbol table
--13517-- REDIR: 0x43c0b10 (rindex) redirected to 0x4025ae0 (rindex)
--13517-- REDIR: 0x43c07f0 (__GI_strlen) redirected to 0x4026050 (__GI_strlen)
--13517-- REDIR: 0x43bc660 (calloc) redirected to 0x402417f (calloc)
--13517-- REDIR: 0x43bdec0 (realloc) redirected to 0x4024f4a (realloc)
--13517-- REDIR: 0x43c1930 (memset) redirected to 0x401f44c (_vgnU_ifunc_wrapper)
--13517-- REDIR: 0x445bef0 (__memset_sse2) redirected to 0x4027420 (memset)
--13517-- REDIR: 0x43bce60 (free) redirected to 0x4024ab5 (free)
--13517-- REDIR: 0x43c1f20 (memcpy) redirected to 0x401f44c (_vgnU_ifunc_wrapper)
--13517-- REDIR: 0x445d000 (__memcpy_ssse3) redirected to 0x40267f0 (memcpy)
--13517-- REDIR: 0x43c32b0 (strchrnul) redirected to 0x4027510 (strchrnul)
 0 1 4 9
 1 0 7 9
 2 3 5 9
 3 2 6 9
 4 0 5 8
 5 2 4 8
 6 3 7 8
 7 1 6 8
 8 4 5 6 7
 9 0 1 2 3
==13517== 
==13517== HEAP SUMMARY:
==13517==     in use at exit: 456 bytes in 21 blocks
==13517==   total heap usage: 73 allocs, 52 frees, 3,428 bytes allocated
==13517== 
==13517== Searching for pointers to 21 not-freed blocks
==13517== Checked 425,428 bytes
==13517== 
==13517== 200 (120 direct, 80 indirect) bytes in 10 blocks are definitely lost in loss record 2 of 3
==13517==    at 0x402425F: calloc (vg_replace_malloc.c:467)
==13517==    by 0x8048DF7: main (startdIII.cpp:76)
==13517== 
==13517== 256 bytes in 1 blocks are definitely lost in loss record 3 of 3
==13517==    at 0x402425F: calloc (vg_replace_malloc.c:467)
==13517==    by 0x40C9A78: igraph_vector_init (vector.pmt:123)
==13517==    by 0x8048B43: main (startdIII.cpp:49)
==13517== 
==13517== LEAK SUMMARY:
==13517==    definitely lost: 376 bytes in 11 blocks
==13517==    indirectly lost: 80 bytes in 10 blocks
==13517==      possibly lost: 0 bytes in 0 blocks
==13517==    still reachable: 0 bytes in 0 blocks
==13517==         suppressed: 0 bytes in 0 blocks
==13517== 
==13517== ERROR SUMMARY: 2 errors from 2 contexts (suppressed: 27 from 6)
--13517-- 
--13517-- used_suppression:     27 dl-hack3-cond-1
==13517== 
==13517== ERROR SUMMARY: 2 errors from 2 contexts (suppressed: 27 from 6)

What’s wrong? I’ve been trying differents way but it continue with the same output.

Thank advance

vacing

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1 Answer

  1. Editorial Team

    1. Your vector v is never destroyed – that’s why you got the second warning in Valgrind.

    2. You must pass an initialized but empty igraph_vector_ptr_t into igraph_neighborhood, otherwise it will simply get rid of the pointers (and the vectors) already in there and allocate new ones. This is because igraph_neighborhood does not know how the pointers in igraph_vector_ptr_t were allocated and what destructor should be called on them (if any), so it tries to do the least damage and simply ignore them. So, no need to pre-load your igraph_vector_ptr_t with vectors in the first for loop. This gets rid of the first warning.

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