That should work just fine. Note, however, that it will take the variable from the environment of the PostgreSQL server process, not your current client process.

There are certainly some ways that such a system could be attacked, although it sounds like in this case it's unlikely that any given attack would matter. A few particular ones, though: An attacker might open lots of connections to your server, constantly saturating its connection limit (DoS). ... or forcing them to be open as long as possible, consuming system fds/handles and potentially causing DoS. ... or trying to open a huge number at once which, depending on how your server is implemented, might cause too many threads/processes (DoS). ... or fill up the recv buffer on each, trying to deplete RAM (DoS). There's also the attacks on the authenticity of the data. You could address that by including a timestamp and digital signature on the data, which clients could then verify using your public key (and their own, hopefully synchronized, clocks). Realistically, you're almost certainly fine given the scenario as described, though.

What changed since the book seems to be the introduction of position independent executables (PIE) since Debian 9 (see https://stackoverflow.com/q/42906761/18048105 stackoverflow question). Apparently, PIE does a few things, among them shifting the stack towards lower addresses (starting with 0x00). If somebody can explain what it does and why, that would answer all my questions. For now, including the flag gcc -no-pie does the trick! With this flag, the stack addresses are now similar to what I see in the book.

The paranoia level should depend on: the underlying OS Modern system offer process isolation: even when a process goes fully mad, it can neither write into the kernel memory pages, nore in memory pages from other processes. Things can be different in embedded systems (or if good old MS/DOS is still being used): a process invoking UB can easily crash the system possibly in the middle of a file system operation and end with a no more bootable system. the evilness of the programmer. Most of use do not invoke UB too often, or do not try to use UB to circumvent system protections. The more you try that, the higher the risk of breaking the system the caution used during tests. Normally, test should only occur using unprivileged accounts limiting the possible damages to what is accessible to that user. But certain part of code do require admin authorizations, for example to access privileged network ports on Unix-like systems. The more code being run under admin account the higher the risk. The damage level to be expected: application crash: high risk as soon as UB has been invoked. Just restart the app (if possible after fixing the error...) system crash: should not be directly possible, unless your run your tests under an privileged account. But a simple reboot should be enough. damages to application files: Once UB has been invoked, the application could continue to run and write garbage to application files. It can require a full re-install of the application damages to system files: should not be possible under you run your tests under a privileged account. But you could have to reinstall the whole system from scratch hardware damages: This one should be very uncommon. It should only occur if the system was tweaked for example with higher frequences than recommended by the hardware provider. The application could then enter a loop asking to much on the hardware and leading to too much heat and irreversible damages. Honestly I have no real world example of that TL/DR: if you use a non priviledged account in your developements, then you should be prepared to reinstall only your dev environment. If you use an admin account, you should be prepared to re-install the whole system. But having to replace the hardware should only occur for very special use cases...

I can only control the access to the socket at user level (or user group) Unfortunately, if there's no parent-child or sibling relationship between the processes, this will always be the case. The security model of all major operating systems, both Windows and Unix-like, is primarily user-based. Even when you can https://unix.stackexchange.com/q/16300/334903 , you can't tell whether or not some other process is looking into its memory or even outright puppeting it using debugger APIs or similar. You can't even necessarily tell if its the program you think it is (e.g. on Linux I could create a process /bin/AndreaClient that connects to your IPC but does what I want, and then delete the file and replace it with your official AndreaClient). It is possible to exclude some processes that have lower-than-full-user privileges (that is, processes which are less than "full trust" and run in a sandbox) easily enough - just don't make your IPC endpoint visible to the sandbox - but you can't prevent any process running with at least as much privilege as your usual client from connecting. If the two processes are parent/child or similar, you can perhaps set up the connection between them without ever exposing it to other processes, by using https://linux.die.net/man/2/socketpair or https://linux.die.net/man/2/pipe to ensure the connection is already open before spawning the new process (and passing the open file descriptor directly to the new process). However, even there, you can't prevent the case that some other process (a debugger with the necessary privileges) attaches to the running process after the fact, and indeed you'd need to be careful how you launch the child process (open file, verify its correctness using e.g. cryptographic hash or signature verification, https://man7.org/linux/man-pages/man2/execveat.2.html the still-open file descriptor) if there's any risk that another process would overwrite the child process binary. Note that adding encryption wouldn't even help, here, because where are you going to store the key? Anywhere you could put the key - in a separate file, embedded in the binary (please don't), in an environment variable, etc. - it will be at minimum also visible to the superuser and any debuggers of either process, probably visible to all processes running as the same user, and possibly visible to all users. With that said... why does it matter? If you don't trust the code running as the same user (or group), or the superuser, why are you trying to put any secrets on the machine at all? It's compromised! The attacker already has control, it's game over, man. It's perfectly reasonable to block access to limited-privilege peer users, and to sandboxed processes, by putting your local (unix) socket / named pipe / memory-mapped file / ALPC endpoint, etc. out of reach of such untrusted entities (protecting it using file permissions / ACLs / mandatory integrity controls). Approximately every form of IPC (with the notable exception of loopback network sockets) support such access controls. As for which form to use, that depends a lot on your use case. Local (Unix) sockets (which also work on Win10 and later) have the advantage of being standardized and cross-platform, and have some useful features (e.g. passing a file descriptor across them in a useful way), but they are also a fairly low-level communication tool; you'll get a binary stream you can read and write to, and need to design the protocol and implement the server and client on top of it. You can reuse existing protocols and libraries for them, of course, provided that the library accepts an open socket fd (or can open a local path instead of a network address). Alternatively, higher-level communication channels may be available. Some common options (at various levels of abstraction) are Remote Procedure Calls (such as MSRPC which is technically cross-platform but de-facto Windows only, gRPC which is cross-platform, etc.), System V message queues (implemented on most *nix systems), D-bus (present on most Linux desktops and some other systems), Grand Central Dispatch (from Apple but technically cross-platform), and many others. Unless you're building for a very low-resource embedded platform, you probably have options that might be more convenient than local sockets. On the other hand, sometimes simplicity is desired; possibly all you need is a single unidirectional pipe (FIFO). In any case, all of these mechanisms are going to primarily be secured by the user-based security model of the underlying OS.

The positioning in the text files has already been written in the commentary - https://ru.stackoverflow.com/users/182825/ant ♪ Anyway, your challenges. fseek They're putting a position in the file just at the beginning or the end, and it's going to be all right here https://msdn.microsoft.com/ru-ru/library/75yw9bf3.aspx : Properly searching 0 relative to any origin) In addition to one challenge:fseek(file, 8, SEEK_END); You're trying to get out of the file, 8 bytes further than it ends. This is not prohibited in principle (see above). https://msdn.microsoft.com/ru-ru/library/75yw9bf3.aspx but empty places will be filled with zeros. Is that exactly what you want to behave?if (file == NULL) { fclose(file); Don't close. not open file. That's what it says. https://msdn.microsoft.com/ru-ru/library/fxfsw25t.aspx :Fclose's function is closing the stream. If the stream parameter is NULL, the inadmissible parameter shall be produced as described in the parameter verification section. If performance can continue, fclose sets errno in EINVAL and returns EOF. It is recommended that the stream indicator be always checked before the function is challenged. file = fopen(filename, "w"); fclose(file); file = fopen(filename, "r"); Here you create an empty file and open it for reading. What can I read? file = fopen(filename, "w"); fclose(file); file = fopen(filename, "r+"); There's an empty file here, then it opens for recording and reading. But it's a challenge to make-- file = fopen(filename, "w+"); (See. https://msdn.microsoft.com/ru-ru/library/yeby3zcb.aspx )

If you can't. strtoke.g. (in the assumption that the word is only symbols) isalphaint main() { char * str = " cbvahv xchnvz jh jhs sdfjhgbvjhsbvdf sdfh "; int count = 0, posmin = -1, countmin = strlen(str); for(int i = 0; i < strlen(str);) { while(str[i] && !isalpha(str[i])) ++i; if (str[i] == 0) break; int pos = i; while(str[i] && isalpha(str[i])) ++i; count = i - pos; if (count < countmin) { countmin = count; posmin = pos; } } for(int i = posmin; i < posmin+countmin; ++i) putchar(str[i]); putchar('\n'); printf("Len = %d, pos = %d\n",countmin,posmin); }

Write the right cycle condition.while( *(array+begin)!=' ' && *(array+begin)!='.' && *(array+begin)!=',' && *(array+begin)!='\0'){ printf("%c",*(array+begin++)); Truth before this cycle at the end if Add the proposals.++begin;

Technically, you're just losing qualification. const I'm not sure if you're not going to change. If this change is not clear, a lot of trouble can be obtained, for example, without problems changing constant variables. So the compiler needs to be clearly told that you understand what you're doing, and you're taking responsibility for yourself using it. const_cast:const int** A = const_cast<const int**>(new int* [n]); int** B = const_cast<int**>(new const int* [n]); And it's not. Announcementwhat is really just const int** A; int** B; You're the one who's already initiated the declared variables.

In order to provide a performance indicator in a managed form, a delegate should be used. The delegate will also have to make a call agreement with the assistance of the https://msdn.microsoft.com/en-us/library/system.runtime.interopservices.unmanagedfunctionpointerattribute.aspx :[UnmanagedFunctionPointer(CallingConvention.Cdecl)] delegate byte Callback1Type();

char *packet; /* ... */ memcpy(packet,&a,4); You've announced the index, but you haven't given the memory he's pointing to. Either:char packet[4]; // или сколько вам надо or:char *packet = new char[4]; // или сколько вам надо P.S. You are. C++ What do you want?

Type char may behave either as a type signed char or type unsigned char Depending on the identified compilator options.In your case, type char acting like a type signed char♪For type signed char maximum positive value equal to 127 or 16 0x7F♪If you want a positive code, write it.printf("%d",(unsigned char)'А'); However, the Russian letter should not be presented as a multidisciplinary constant.

You can count it. http://ideone.com/ThL4Zy #include <stdio.h> int main(void) { int x; char s[2]; while (1) { switch (scanf("%d%1[C]", &amp;x, s)) { case -1: return 0; case 2: printf("%d\n", x); break; default: scanf("%*[^-+0-9]"); } } }

b = (a & 0x0000FFFF00000000) >> 32; Keywords for search - battle mask and shift. Read: http://www.c-cpp.ru/books/bitovye-operatory ♪

http://www.mingw.org/ doesn't support the youth version. WinMainso we need to use a unique version:INT WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, INT nCmdShow) a command line parameters obtained through GetCommandLineW():int argc; wchar_t** argv = CommandLineToArgvW(GetCommandLineW(), &argc); for (int i = 0; i < argc; i++) { //output argv[i] } Get out of here: https://stackoverflow.com/questions/38418188/winmain-compiles-but-wwinmain-does-not-in-codeblocks On the other hand, https://mingw-w64.org/doku.php (which is the fort and the ideo of MinGW) https://sourceforge.net/p/mingw-w64/wiki2/Unicode%20apps -municodewhich enables a binary with a young version WinMain♪

Through the OpenGL, the simplest and fastest part is to create a textur and put it on the screen (using the kwads and shepherds, since the OpenGL ES issue).

If you don't take the seal off.if ((file2 = fopen("file2,txt", "rb")) != NULL) ^^^ whether your program, C or C+++, is written the first comparison.if (ch1 != ch2) may result in incorrect results, as variables ch1 and ch2 declared as having type boolbool ch1, ch2; Therefore, provided if They will be converted either to 1 or 0. I mean, you're not gonna compare the symbols that you read, but you're gonna compare whether there's one symbol from one or the other from one or the other.More than the cyclewhile (ch1 != EOF); You'll always be true, because of the reverse transformation. ch1 You're not getting any. -1which usually corresponds EOFAnd you'll get it again, either 0 or 1. I mean, you'll have an endless cycle.If you compare text files, you better open them in text mode and compare them fast.If you want to compare the files as binary, you'll have to count the symbols of the new line. '\n'to tell me where the line is.

Battle operations are designed to deal with battles. There's no match between decimal numbers and bat masks. There's a match between the 16-digits and the bat mask.You just need to split the number by degree 10 or take the balance of the level 10 to get a part of the number.For example, to get 2300 Number 112 300 You need to write an expression.112300 % 10000 With regard to operators moving the mainframe and duct, in fact, they either target the number by 2 or multiplied the number by 2.For example, if you have a number 3which can be seen in two ways 0011after the operator has been used >> You'll get it. 0001I mean, 1. True 3 / 2 equals 1 in counted ears. If you're using the operator ROP, it's smart, that's when you move to the left, you' the number. 0110which corresponds to 6.In the case of bat masks, it is very easy to write a function that provides a mask for the allocation of some continuous section of the bats.For example#include <iostream> #include <iomanip> unsigned int get_mask( unsigned int pos, unsigned int n ) { return ~( ~0 << n ) << pos; } int main() { unsigned int x = 0xAB; unsigned int mask = get_mask( 0, 4 ); std::cout &lt;&lt; std::hex &lt;&lt; ( x &amp; mask ) &lt;&lt; std::endl; mask = get_mask( 4, 4 ); std::cout &lt;&lt; std::hex &lt;&lt; ( x &amp; mask ) &lt;&lt; std::endl; return 0; } programme withdrawalb a0 That is, in the first case of the mask, 4 bats were allocated. The other battles of the number fell. In the second case, the following four bats were allocated and the other bats dropped.Or a more pronounced program.#include <iostream> #include <iomanip> unsigned int get_mask( unsigned int pos, unsigned int n ) { return ~( ~0 << n ) << pos; } int main() { unsigned int x = 0x12345678; for ( size_t i = 0; i &lt; 2 * sizeof( unsigned int ); i++ ) { unsigned int mask = get_mask( 4 * i, 4 ); std::cout &lt;&lt; std::hex &lt;&lt; ( x &amp; mask ) &lt;&lt; std::endl; } return 0; } Her withdrawal to the console8 70 600 5000 40000 300000 2000000 10000000

There are ready-to-be Ruthing libraries, maybe you should use them or watch implementation.In your case, you should see: http://arduino.cc/en/Reference/PROGMEM &quot; . In particular, use data type PROGMEM variable[] = {}; for byte A[] = { 0x7C, 0x12, 0x11, 0x12, 0x7C }; and F() for else if (value == "!") { addLetter(screamer); }♪ Because // и т.д для каждого символа - it's just a pity. You can't use the ASCII codes and you can't bear it. if- Who?

Two main ways-- https://golang.org/cmd/cgo/ and https://golang.org/misc/swig/stdio/ ♪ (main.c):// main.c #include <stdio.h> void f(void) { printf("Hello, world!\n"); } And main.go:// main.go package main // #include "main.c" import "C" func main() { C.f() } Put both in one folder, you call. go build and ready.