向量 push_back std::length_error: vector" 失败

Question

I have a problem, I need to push_back a srtuct. structure is like that.

struct RChar
{
  int x;
  int y;
  string letter;
}
struct PResult
{
  int conf;
  string name;
  std::vector<RChar> char_details;
};
class IResults
{
  IResults(){};
  ~IResults(){};
  float processing_time_ms;
  int index;
  std::vector<PResult> topPResults;

};

// use case
 
IResults* myres = new IResults();
PResult res;
res.conf = 30;
res.name = "xyz";
......
......
myres->topPResults.push_back(res); // here a run time exception thrown  

In above code i am performing a simple operation. the exception thrown on run time is A/libc: /usr/local/google/buildbot/src/android/ndk-release-r20/external/libcxx/../../external/libcxxabi/src/abort_message.cpp:73: abort_message: assertion "terminating with uncaught exception of type std::length_error: vector" failed . The exception looks like vector memory allocation failed. I am unable to trace the issue exactly what is causing the problem here.

Answer 1

There is a memory overrun somewhere. The vector container is a data structure with pointers; if some other code writes over these pointers, it tries to access invalid memory and fails.

The exception type ( length_error ) may or may not be relevant. Imagine some faulty code wrote -1 over the length member of the vector class - this would confuse the vector code to think its length is invalid.

See here for details on how to fix.