add pointer to structure array to std::map - c++

Question

I want to keep an array of data index by a string and I thought I'd best use std::map for this purpose. I have below example code:
typedef struct MyType_s {
long long timestamp;
int cnt;
bool parked;
}MyType;
static MyType *list = {0};
static int listcnt = 0;
//-------------------------------------------------------------------------------------------------
int map_add_item(std::map<std::string, MyType*> *pmap, std::string str, long long tmestmp)
{
if (listcnt == 0){
list =(MyType*)malloc(sizeof(MyType));
if (list)
listcnt++;
else
return ENOMEM;
}
if (realloc(list,sizeof(MyType)*(++listcnt))==0)
return ENOMEM;
list->timestamp = tmestmp;
if (!(str.length()&&tmestmp&&pmap))
return EINVAL*-1;
if (pmap->insert(std::make_pair(str, &list[listcnt-1])).second == false){
pmap->find(str)->second->timestamp = tmestmp;
return EEXIST*-1;
}
return OK;
}
which compiles fine but I get a mem dump like this when I run it:
*** Error in `./std_map': double free or corruption (fasttop): 0x000000000226ec20 ***
======= Backtrace: =========
/lib/x86_64-linux-gnu/libc.so.6(+0x777e5)[0x7f19fb6267e5]
/lib/x86_64-linux-gnu/libc.so.6(+0x8037a)[0x7f19fb62f37a]
/lib/x86_64-linux-gnu/libc.so.6(+0x83350)[0x7f19fb632350]
/lib/x86_64-linux-gnu/libc.so.6(realloc+0x179)[0x7f19fb633839]
./std_map[0x4013c8]
./std_map[0x40198d]
/lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xf0)[0x7f19fb5cf830]
./std_map[0x401259]
======= Memory map: ========
00400000-00404000 r-xp 00000000 08:02 6054199 /path/to/src/tmp/std_map
00604000-00605000 r--p 00004000 08:02 6054199 /path/to/src/tmp/std_map
00605000-00606000 rw-p 00005000 08:02 6054199 /path/to/src/tmp/std_map
0225d000-0228f000 rw-p 00000000 00:00 0 [heap]
7f19f4000000-7f19f4021000 rw-p 00000000 00:00 0
7f19f4021000-7f19f8000000 ---p 00000000 00:00 0
7f19fb2a6000-7f19fb3ae000 r-xp 00000000 08:02 28971840 /lib/x86_64-linux-gnu/libm-2.23.so
7f19fb3ae000-7f19fb5ad000 ---p 00108000 08:02 28971840 /lib/x86_64-linux-gnu/libm-2.23.so
7f19fb5ad000-7f19fb5ae000 r--p 00107000 08:02 28971840 /lib/x86_64-linux-gnu/libm-2.23.so
7f19fb5ae000-7f19fb5af000 rw-p 00108000 08:02 28971840 /lib/x86_64-linux-gnu/libm-2.23.so
7f19fb5af000-7f19fb76f000 r-xp 00000000 08:02 28971844 /lib/x86_64-linux-gnu/libc-2.23.so
7f19fb76f000-7f19fb96f000 ---p 001c0000 08:02 28971844 /lib/x86_64-linux-gnu/libc-2.23.so
7f19fb96f000-7f19fb973000 r--p 001c0000 08:02 28971844 /lib/x86_64-linux-gnu/libc-2.23.so
7f19fb973000-7f19fb975000 rw-p 001c4000 08:02 28971844 /lib/x86_64-linux-gnu/libc-2.23.so
7f19fb975000-7f19fb979000 rw-p 00000000 00:00 0
7f19fb979000-7f19fb98f000 r-xp 00000000 08:02 28971397 /lib/x86_64-linux-gnu/libgcc_s.so.1
7f19fb98f000-7f19fbb8e000 ---p 00016000 08:02 28971397 /lib/x86_64-linux-gnu/libgcc_s.so.1
7f19fbb8e000-7f19fbb8f000 rw-p 00015000 08:02 28971397 /lib/x86_64-linux-gnu/libgcc_s.so.1
7f19fbb8f000-7f19fbd01000 r-xp 00000000 08:02 23072621 /usr/lib/x86_64-linux-gnu/libstdc++.so.6.0.21
7f19fbd01000-7f19fbf01000 ---p 00172000 08:02 23072621 /usr/lib/x86_64-linux-gnu/libstdc++.so.6.0.21
7f19fbf01000-7f19fbf0b000 r--p 00172000 08:02 23072621 /usr/lib/x86_64-linux-gnu/libstdc++.so.6.0.21
7f19fbf0b000-7f19fbf0d000 rw-p 0017c000 08:02 23072621 /usr/lib/x86_64-linux-gnu/libstdc++.so.6.0.21
7f19fbf0d000-7f19fbf11000 rw-p 00000000 00:00 0
7f19fbf11000-7f19fbf37000 r-xp 00000000 08:02 28971842 /lib/x86_64-linux-gnu/ld-2.23.so
7f19fc0fc000-7f19fc102000 rw-p 00000000 00:00 0
7f19fc135000-7f19fc136000 rw-p 00000000 00:00 0
7f19fc136000-7f19fc137000 r--p 00025000 08:02 28971842 /lib/x86_64-linux-gnu/ld-2.23.so
7f19fc137000-7f19fc138000 rw-p 00026000 08:02 28971842 /lib/x86_64-linux-gnu/ld-2.23.so
7f19fc138000-7f19fc139000 rw-p 00000000 00:00 0
7ffd68bf4000-7ffd68c16000 rw-p 00000000 00:00 0 [stack]
7ffd68d88000-7ffd68d8b000 r--p 00000000 00:00 0 [vvar]
7ffd68d8b000-7ffd68d8d000 r-xp 00000000 00:00 0 [vdso]
ffffffffff600000-ffffffffff601000 r-xp 00000000 00:00 0 [vsyscall]
Command terminated
gdb doesn't give me much more information too.
This is after I call the function like this from main():
int main()
{
int ret = 0;
std::map<std::string, MyType*> mapOfWords;
std::cout << map_add_item(&mapOfWords,"earth",time(NULL)+1) << std::endl;
return 0;
}
I'm wondering what I'm doing wrong, double free or corruption obviously is a hint but I'm not sure how to interpret this and I can't pinpoint the problem....

Answer 1

For a working solution, I replaced the global static variable and the pointers in the map with data that is located directly in the map. Plus I removed the typedef from the struct and declared it the C++ way instead, as in:
std::map<std::string, MyType> *pmap
struct MyType {
long long timestamp;
int cnt;
bool parked;
};