"large" project, crashes, variable "overlap", gdb

[cn00by]

hello,
i searching for days for an Segmentation fault.

What i ve done:
i try:
- valgrind
- gdb
- comment the most c++ code out

my problem, if i comment out one more header i got an Segmentation fault.
i try different headers, always the same.
-> some more code -> crash (which header i comment out, is equal)

i try to rebuild the error, create an new project, copy the source code, run...
all okay. i can not replicate the error, with "new" source code. *argh*


my cood looks like

<code>
#include <iostream>
#include <vector>

class interface{
public:
void init(void);
private:
std::vector<unsigned char> m_data;
};

void interface::init()
{
m_data.clear();
m_data.resize(8192);
}

class m;

class minterface : public interface{
public:
minterface();
void init(m* value);
private:
m* m_ptr;
};

minterface::minterface()
{
m_ptr = nullptr;
}

void minterface::init(m* value)
{
m_ptr = value;
interface::init();
}

class m{
public:
void init(void);
private:
minterface m_i;
};

void m::init(void)
{
m_i.init(this);
}

int main() {
m a;
a.init();
return 0;
}
</code>

if i got an segmentation fault the address from the variable m_ptr is too close to the m_data,
check my gdb out:
(gdb) break minterface::init
(gdb) r
(gdb) print m_data
$1 = std::vector of length 0, capacity 0
(gdb) print &m_data
$2 = (std::vector<unsigned char, std::allocator<unsigned char> > *) 0xbefffc8c
(gdb) print m_ptr
$3 = (m_ptr *) 0x0
(gdb) print &m_ptr
$4 = (m_ptr **) 0xbefffc8c

after i set the m_ptr variable i got this output:

(gdb) print m_ptr
$7 = (m_ptr *) 0xbefff9dc
(gdb) print m_data
$8 = std::vector of length 1090520612, capacity 1090520612 = {132 '\204', 24 '\030', 4 '\004', 0 '\000', 8 '\b', 49 '1', 6 '\006', 0 '\000', 0 '\000', 0 '\000', 0 '\000',
0 '\000', 0 '\000', 0 '\000', 0 '\000', 0 '\000', 0 '\000', 0 '\000', 0 '\000', 0 '\000', 248 '\370', 249 '\371', 255 '\377', 190 '\276', 0 '\000', 0 '\000', 0 '\000', 0 '\000',
0 '\000', 0 '\000', 0 '\000', 0 '\000', 32 ' ', 2 '\002', 0 '\000', 0 '\000', 8 '\b', 0 '\000', 0 '\000', 0 '\000', 66 'B', 0 '\000', 0 '\000', 0 '\000', 16 '\020', 250 '\372',
255 '\377', 190 '\276', 0 '\000', 0 '\000', 0 '\000', 0 '\000', 0 '\000', 0 '\000', 0 '\000', 0 '\000', 0 '\000', 0 '\000', 0 '\000', 0 '\000', 124 '|', 0 '\000', 0 '\000',
0 '\000', 16 '\020', 1 '\001', 0 '\000', 0 '\000', 40 '(', 250 '\372', 255 '\377', 190 '\276', 0 '\000', 0 '\000', 0 '\000', 0 '\000', 0 '\000', 53 '5', 255 '\377', 182 '\266',
0 '\000', 48 '0', 226 '\342', 182 '\266', 9 '\t', 2 '\002', 0 '\000', 0 '\000', 64 '@', 0 '\000', 0 '\000', 0 '\000', 0 '\000', 0 '\000', 0 '\000', 0 '\000', 68 'D', 250 '\372',
255 '\377', 190 '\276', 0 '\000', 0 '\000', 0 '\000', 0 '\000', 0 '\000', 49 '1', 216 '\330', 182 '\266', 9 '\t', 2 '\002', 0 '\000', 0 '\000', 0 '\000', 150 '\226', 104 'h',
126 '~', 4 '\004', 1 '\001', 0 '\000', 0 '\000', 92 '\\', 250 '\372', 255 '\377', 190 '\276', 0 '\000', 0 '\000', 0 '\000', 0 '\000', 0 '\000', 0 '\000', 0 '\000', 0 '\000',
4 '\004', 1 '\001', 0 '\000', 0 '\000', 244 '\364', 251 '\373', 255 '\377', 190 '\276', 16 '\020', 0 '\000', 0 '\000', 0 '\000', 0 '\000', 59 ';', 8 '\b', 0 '\000', 0 '\000',
0 '\000', 0 '\000', 0 '\000', 124 '|', 250 '\372', 255 '\377', 190 '\276', 11 '\v', 0 '\000', 0 '\000', 0 '\000', 83 'S', 101 'e', 99 'c', 116 't', 105 'i', 111 'o', 110 'n',
108 'l', 101 'e', 115 's', 115 's', 0 '\000', 116 't', 7 '\a', 4 '\004', 0 '\000', 0 '\000', 0 '\000', 0 '\000', 0 '\000', 0 '\000', 0 '\000', 0 '\000', 0 '\000', 0 '\000',
0 '\000', 0 '\000', 0 '\000', 0 '\000', 0 '\000', 0 '\000', 0 '\000', 0 '\000', 0 '\000', 0 '\000', 0 '\000', 0 '\000', 0 '\000', 0 '\000', 0 '\000'...}
(gdb)

m_data is corrupted :-(

Have anybody some idea?

thanks a lot!

[Peter87]

The code that you have posted does not contain any header files.

If the segfault only happens when you change the code, never after a fresh build, then maybe there is something wrong with how your build process is set up. When a header file is modified all .cpp files that includes that header file (either directly or indirectly through another header) needs to be recompiled.