Program in c++ hangs when I use a function to pick up a file name

Question

I’m making a small IDE in c++ and I’m having trouble getting a file name.
ex: the full file path is "Keywords//cplusplus.txt" but the file name is "cplusplus.txt".
So I wrote a function to get his real name.

char* Io::GetRealName(int file)
{
    char* full_name=GetName(file);
    int last_bar=0;
    for(int i=0;i<strlen(full_name);i++)
    {
        if(full_name[i]=='/')
        {
            last_bar=i+1;
        }
    }
    char* real_name=(char*) malloc((strlen(full_name)-last_bar)*sizeof(char));
    memcpy (real_name,full_name+last_bar,strlen(full_name));
    real_name[strlen(full_name)-last_bar]='\0';
    return real_name;
}

The Getname(int) function takes the full path of the file.
I don’t know what’s wrong, because when I finished the job was working, however, after a while began to brake and now sometimes hangs and others not.
Does anyone know what’s wrong? The pointers maybe?

Answer 1

The problem is in this line of code:

memcpy (real_name,full_name+last_bar,strlen(full_name));

The function memcpy is copying extra bytes, ie the function is writing out of memory allocated by malloc. It would be right:

memcpy(real_name, full_name+last_bar,(strlen(full_name)-last_bar)*sizeof(char));

Now yes, the amount of bytes being copied is the same as what was allocated in malloc.