memory

问题 I am trying to implement shared memory on embedded device with uClinux. My C source #include <stdio.h> #include <sys/shm.h> #include <sys/stat.h> #include <sys/socket.h> #include <errno.h> //using namespace std; int main() { int segment_id; segment_id = shmget(04, getpagesize(), IPC_CREAT | 0666); printf("Page size - %d\n",getpagesize()); printf("Error in socket - %d\n",errno); } I get an error Page size - 4096 Error in socket - 38 Can anyone help me? Thanks. 回答1: You need to test segment_id

问题 Looks like the memory required to hold a memory structure with Javascript Objects doesn't only rely on the number of stored objects but also the used keys. Let's write, for example, this simple code in fiddlejs (link below): for (var i=0; i<500; i++) { o[i]={}; for (var j=0; j<500; j++) { o[i][j]={}; o[i][j]['abc'] = {}; } } https://jsfiddle.net/9Lespw7g/ Then run the script and open the Chrome memory tab (or take a memory snapshot with Firefox). At this point the profiler should show

问题 This question already has an answer here : What happens in the heap when class A inherits class B in Java (1 answer) Closed 1 year ago . Consider a Superclass A and a derived class B whereas A contains a private variable x . B contains an explicit super() call as first argument inside its constructor while there might be some other variables of B like y and z . As far as I know there is no inheritance for private fields. Does that mean private fields will not get instantiated while executing:

问题 I am currently attempting to read/write to memory through the use of JNA for Java. For the past week I have tried a multitude of solutions, mostly from similar projects I have found online, but nothing has resolved my problem. I know I am receiving the correct process ID of the program, then I create a Pointer using the openProcess method. Then I call getBaseAddress using the newly created Pointer. The problem I believe lies within the EnumProcessModules/Psapi method/class. Truthfully I am

问题 In debug mode I saw that the pointers have addresses like 0x01210040, but as I realized, 0x means hexadecimal right? And there're 8 hex digits, i.e. in total there're are 128 bits that are addressed?? So does that mean that for 32-bit system the first two digits are always 0, and for a 64-bit system the first digit is 0? Also, may I ask that, for a 32-bit program, would I be able to allocate as much as 3GB of memory as long as I remain in the heap and use only malloc()? Or is there some

问题 Looking for a memory leak I recently noticed that the Virtual Memory value reported by Process Explorer (procexp.exe by Microsoft/Sysinternals v16.26) is very high - like about 2.1TB where my laptop has 32GB RAM running Win 10Pro X64. Here for example, it reports that the virtual memory size of a Chrome.exe process is 2,151,819,136 KB. Any idea what may be causing that? 回答1: Thanks that-other-guy for the tip. As Alex Ionescu explains in his post (How Control Flow Guard Drastically Caused

问题 What tools or processes would you recommend for debugging ctypes memory issues? How is it possible to print the contents of an array but not be able to copy it? I have narrowed my problem down to the following lines: [ ... lots of code ...] valid_data_as_bytes = bytearray(self._output_buffer[:result]) print("valid_data_as_bytes:",valid_data_as_bytes) print("len(valid_data_as_bytes):", len(valid_data_as_bytes)) assert len(valid_data_as_bytes) == result Buffer = ctypes.c_ubyte * len(valid_data

问题 I expect that that data begins at for example 0x100 (memory location) and everything before that it's commands... But I am really not sure! Thanks for help! okay, to detail my question: I see the memory as a long array with one byte space. The space is filled with hex numbers. But the variables can fill the memory from for example 0x0000 - 0xffff. But how do you know that for example 0x002f is a command (for example 'mov') or just a number as data? 回答1: The CPU doesn't know. It's all about

问题 I would like to know what precisely is happening since php script runs the query to the moment when database returns data and php script starts to fetch them. In theory, I have a Postgre database with huge table, talking about 10/20 million records with 20+ columns and I have a php script which is requesting all that rows from database to be placed in, lets say, some file. My knowledge is: php script runs the pg_query command with sql query through postgres php driver/extension query is

问题 I would like to know what precisely is happening since php script runs the query to the moment when database returns data and php script starts to fetch them. In theory, I have a Postgre database with huge table, talking about 10/20 million records with 20+ columns and I have a php script which is requesting all that rows from database to be placed in, lets say, some file. My knowledge is: php script runs the pg_query command with sql query through postgres php driver/extension query is