ptr technologies

1. const int *ptr = NULL; 1) Represents a pointer variable to a symbolic constant, and the pointer variable itself is not const so it can point to other variables.2) The role of Const can be seen as "forbidden by *ptr" To change the value of the variable that the PTR points to, but the variable being pointed to can change its own definition .eg:const int i = 1, i

Container_of (PTR, type, member) is used for the member Member and the member pointer PTR (address) and struct type in a known struct, returns the pointer (the address) of the struct where the member is located, for example, known. Struct student { Char * Name; Int age; } Int * page = age; Container_of (page, struct student, A. Age); returns the address of. This method can be implemented in three st

DWORD dual is the abbreviation of Four-byte PTR pointer, that is, the data in Pointer [] is an address value, which points to a dual-type data such as mov eax, dword ptr [12345678] assigns the dual-font (32-bit) data in memory address 12345678 to eax Agree . 5 How long is the data to be processed by the command?CPU commands can process data in two dimensions: byte (8 bits) and word (16 bits ). Therefore, i

At first, I did not consider reverse parsing rather than PTR. Later I mentioned these two concepts when I read a technical document, but there is no clear difference. Later I made some research: 1. ptr resolves an IP address to a domain name. ptr-type queries are also standard queries. The question field is queried as 1 and then the Server gives the answer, the

record of china.com is pointing ns1.china.com Internet address = 61.151.243.136 ns2.china.com Internet address = 202.84.1.101zz 3) The specification's MX record should be resolved by the primary domain by a host name (mta.china.com in this case). Again this host name resolves one or more IP addresses (in this case, 211.99.189.179 and 211.99.189.180), and cannot directly resolve an IP address from the primary domain, and the primary domain resolves the The host name should not be the same as t

For this question, the assembly language uses the method to deal with. (1) The size of the data to be processed is indicated by the register name.For example:In the following instruction, the register indicates that the instruction is a word operation:MOV ax,1MOV bx,ds:[0]MOV Ds,axMOV Ds:[0],axInc AXAdd ax,1000 In the following instruction, the register indicates that the instruction is byte-operated:MOV al,1MOV AL,BLMOV al,ds:[0]MOV Ds:[0],alInc ALAdd al,100 (2) In the absence of a register

Today when debugging the program, found a strange problem, before debugging all no problem, this morning added a bit of something, error, jump to debug position, below 4 lines red section1 ; Find next lower page and probe2cs20:3 Sub eax, _pagesize_ ; decrease by PAGESIZE4 test dword ptr [Eax],eax ; Probe page. 5 jmp short cs1067_chkstk ENDP89 EndFeel good strange, and then debugging breakpoints, e

0:000> uf .monitor!main [c:\users\myalias\documents\visual studio 2005\projects\mytest\mytest\main.c @ 32]: 32 0042f780 55 push ebp 32 0042f781 8bec mov ebp,esp 32 0042f783 81eccc000000 sub esp,0CCh 32 0042f789 53 push ebx 32 0042f78a 56 push esi 32 0042f78b 57 push edi 32 0042f78c 8dbd34ffffff lea edi,[ebp-0CCh] 32 0042f792 b933000000 mov ecx,33h 32 0042f797 b8cccccccc mo

you copy a value object, you get a different new copy. Changes made to the copy are not reflected on the original object and vice versa. The String class is an example of a value type class.To make a pointer member behave like a value, you must copy the object that the pointer points to when you copy the Hasptr object:The copy constructor no longer duplicates the pointer, it assigns a new int object, and initializes the object to hold the same value as the copied object. Each object holds a dif

quick look at the precedence table of the operator indicates that the precedence of the postfix operator (16) is higher than the reference operator (15). That is to say, *p++ can be expressed as * (p++), which means that * is acting on p++. First look at the p++ section.2, suffix expression value , p++ value is the value of the p++ expression before p. Suppose you have:int 7 ;p rintf ("%d\n", i++);p rintf ("%d\n", i);The output will be:7 8You can see that the value of i++ is the value before I

The pointer PTR points to the Member member in the struct type. The pointer PTR returns the starting address of the struct type. # Define container_of (PTR, type, member )({\Const typeof (type *) 0)-> member) * _ mptr = (PTR );\(Type *) (char *) _ mptr-offsetof (type, member ));})# Define offsetof (type, member) (size_

This morning the bean accidentally found that the company's DNS server above only the forward parsing, and there is no corresponding PTR record. In other words, the IP address can be resolved by the domain name, but the reverse IP address is not able to find the domain name.1 hours wrote a very simple script, to determine whether there are existing records of the corresponding reverse zone and PTR records,

Analysis of container_of (PTR, type, member)Source: http://gliethttp.cublog.cn# Define container_of (PTR, type, member )({/Const typeof (type *) 0)-> member) * _ mptr = (PTR );/(Type *) (char *) _ mptr-offsetof (type, member ));})# Define offsetof (type, member) (size_t) (type *) 0)-> Member)1. PTR is a physical addre

Http://stackoverflow.com/questions/3228664/why-am-i-able-to-change-the-contents-of-const-char-ptrI passed a pointer to ptr a function whose prototype takes it as const .foo( const char *str );Which according to my understanding means, that it'll is not being able to change the contents of ptr passed. Like in the case of foo( const int i ) . If foo() tries i to chnage the value of, compiler gives error.But h

The meaning and function of PTR in assembly language MoV ax, BX; is to assign the value of the Bx register "in" to ax, because both are word type, so there is no need to add "word"MoV ax, word PTR [BX]; is the data stored in the place where the memory address is equal to the value of the Bx register, and is assigned to ax. Because we only provide a memory address and do not know whether it is byte or wor

[Transfer] http://hi.baidu.com/maxint/blog/item/fc817c2f29881f331e3089ef.html 1. Security pointer Since opencv2.0, many C data structures have changed to C ++ classes. Considering compatibility, the old APIs are retained. In terms of memory management, a secure pointer PTR is provided, so that the old data structure (iplimage, cvmat, etc.) that requires manual memory management does not require manual release. Its usage is as follows:

china.com Ns1.china.com Internet address = 61.151.243.136Ns2.china.com Internet address = 202.84.1.101zz 3) The standard MX record should be resolved by the primary domain to a host name (mta.china.com in this example ), then, one or more IP addresses (211.99.189.179 and 211.99.189.180 in this example) are parsed from the host name, instead of an IP address directly resolved from the primary domain, the host name resolved by the primary domain name cannot be the same as the primary domain na

A title error occurs when you compile a project using G ++ because it is a standard of C ++ 11. Add-STD = C ++ 0x when passing command lines to G ++. You also need to # include In my cmakelists, I want to change it like this: Set (cmake_cxx_flags "$ {cmake_cxx_flags}-STD = C ++ 0x ") References: Http://www.cmake.org/Wiki/CMake/Tutorials/C%2B%2B11Flags Http://stackoverflow.com/questions/12329226/a-short-c-file-and-makefile-i-can-make-in-the-shell-but-get-lots-of-error-wh Https://githu

EDI: Storing stringsAL: Storing characters XEs:[edi]: traversal string, ecx-1 per loop, character X is stoppedA classic way to calculate string lengths in a compilation is to take advantage of this instruction.00406930/$ 89FAmovEdx,edi00406932|. 89c7movEdi,eax;the stored string in EDI00406934|. B9 FFFFFFFFmovecx,-0x1;ECX Put-100406939|. 30c0 XORAl,al;al=0, all strings will be traversed0040693B|.F2:AeRepneSCAs byte ptres:[EDI];iterates through the string in bytes, once per loop cx-100406

Simple simulation for shared_ptr #include Copyright NOTICE: This article for Bo Master original article, without Bo Master permission not reproduced. "C + +" Simple simulation realizes the shared-ptr under the Boost library