下面的测试用例在使用 OpenMP 时在“post MT section”消息之后的循环中在 32 位机器上耗尽内存(抛出 std::bad_alloc),但是,如果 OpenMP 的#pragmas 被注释掉,则代码运行通过完成罚款,所以看起来当内存在并行线程中分配时,它没有正确释放,因此我们用完了内存。
问题是下面的内存分配和删除代码是否有问题,或者这是 gcc v4.2.2 或 OpenMP 中的错误?我也尝试了 gcc v4.3 并得到了同样的失败。
int main(int argc, char** argv)
{
std::cout << "start " << std::endl;
{
std::vector<std::vector<int*> > nts(100);
#pragma omp parallel
{
#pragma omp for
for(int begin = 0; begin < int(nts.size()); ++begin) {
for(int i = 0; i < 1000000; ++i) {
nts[begin].push_back(new int(5));
}
}
}
std::cout << " pre delete " << std::endl;
for(int begin = 0; begin < int(nts.size()); ++begin) {
for(int j = 0; j < nts[begin].size(); ++j) {
delete nts[begin][j];
}
}
}
std::cout << "post MT section" << std::endl;
{
std::vector<std::vector<int*> > nts(100);
int begin, i;
try {
for(begin = 0; begin < int(nts.size()); ++begin) {
for(i = 0; i < 2000000; ++i) {
nts[begin].push_back(new int(5));
}
}
} catch (std::bad_alloc &e) {
std::cout << e.what() << std::endl;
std::cout << "begin: " << begin << " i: " << i << std::endl;
throw;
}
std::cout << "pre delete 1" << std::endl;
for(int begin = 0; begin < int(nts.size()); ++begin) {
for(int j = 0; j < nts[begin].size(); ++j) {
delete nts[begin][j];
}
}
}
std::cout << "end of prog" << std::endl;
char c;
std::cin >> c;
return 0;
}