strcpy adds a null terminator character ‘ ’. You forgot to allocate space for it:
*filename = (char*)realloc(*filename, strlen(*collection_name)*sizeof(char)+5);
You need to add space for 5 characters: 4 for “.tde” suffix, and one more for the ‘ ’ terminator. Your current code allocates only 4, so the last write is done into the space immediately after the block that you have allocated for the new filename (i.e. 0 bytes after it).
Note: Your code has a common problem – it assigns the results of realloc directly to a pointer being reallocated. This is fine when realloc is successful, but creates a memory leak when it fails. Fixing this error requires storing the result of realloc in a separate variable, and checking it for NULL before assigning the value back to *filename:
char *tmp = (char*)realloc(*filename, strlen(*collection_name)*sizeof(char)+5);
if (tmp != NULL) {
*filename = tmp;
} else {
// Do something about the failed allocation
}
Assigning directly to *filename creates a memory leak, because the pointer the *filename has been pointing to below would become overwritten on failure, becoming non-recoverable.
I just had this message because I had changed a class (added a field, so I had changed its size) and not rebuilt all sources that included the header. So some modules still tried to use the old size.