为何内存占用正常 new 也会失败？

[xengine-qyt]

m_saCache = new(std::nothrow) BYTE[CACHE_SIZE];
if (m_saCache == NULL)
return wlet(FALSE, L"new cache is null.");


这是怎么回事？ 搞不懂。。。

[此后三年]

光这样看，new没问题。。。

[falloutmx]

碎片化得太厉害？你先重启下机器，重新建立个项目把代码拷过去，然后试试

[乔巴好萌]

你是VC6.0吗 stackoverflow上有人讨论过 up vote 37 down vote accepted VC6 was non-compliant by default in this regard. VC6's new returned 0 (or NULL). Here's Microsoft's KB Article on this issue along with their suggested workaround using a custom new handler: Operator new does not throw a bad_alloc exception on failure in Visual C++ If you have old code that was written for VC6 behavior, you can get that same behavior with newer MSVC compilers (something like 7.0 and later) by linking in a object file named nothrownew.obj. There's actually a fairly complicated set of rules in the 7.0 and 7.1 compilers (VS2002 and VS2003) to determine whether they defaulted to non-throwing or throwing new. It seems that MS cleaned this up in 8.0 (VS2005)—now it always defaults to a throwing new unless you specifically link to nothrownew.obj. Note that you can specify that you want new to return 0 instead of throwing std::bad_alloc using the std::nothrow parameter: SomeType *p = new(std::nothrow) SomeType; This appears to work in VC6, so it could be a way to more or less mechanically fix the code to work the same with all compilers so you don't have to rework existing error handling.

[xengine-qyt]

不是 是VS2013 UP4，的确看出来 所以我想问问出了内存不够申请失败还会有什么情况让他失败？