我當時玩的是boost :: interprocess,碰巧問了同樣的問題。在最終解決open_or_create需求之前,我做了一點挖掘。然而,深模板意大利麪條的腸子是升壓(我的是1.62),我們發現這種寶石:以上
/*<... snip ...>*/
//This loop is very ugly, but brute force is sometimes better
//than diplomacy. If someone knows how to open or create a
//file and know if we have really created it or just open it
//drop me a e-mail!
bool completed = false;
spin_wait swait;
while(!completed){
try{
create_device<FileBased>(dev, id, size, perm, file_like_t());
created = true;
completed = true;
}
catch(interprocess_exception &ex){
if(ex.get_error_code() != already_exists_error){
throw;
}
else{
try{
DeviceAbstraction tmp(open_only, id, read_write);
dev.swap(tmp);
created = false;
completed = true;
}
catch(interprocess_exception &e){
if(e.get_error_code() != not_found_error){
throw;
}
}
catch(...){
throw;
}
}
}
catch(...){
throw;
}
swait.yield();
}
/* <... snip ...> */
是managed_open_or_create_impl.hpp大約360線,在priv_open_or_create()方法。似乎答案是否定的。不,在嘗試打開共享內存之前,沒有辦法檢查是否創建了共享內存。
來源
2016-12-18 23:13:50
MFT