Search Results

Search found 244 results on 10 pages for 'fprintf'.

Page 6/10 | < Previous Page | 2 3 4 5 6 7 8 9 10  | Next Page >

  • Question with "extern" in C

    - by why
    When programming, I would like to split one large file(which contains main function) to many small files, so there is one common case: functions in small files can modify the var from main file, so i think extern is very useful! for instance: in main.c extern int i = 100; in small.c extern int i; fprintf(stdout, "var from main file: %d\n", i); I just want to know is my understanding right?

    Read the article

  • vim c++ break line

    - by Myx
    Hello: How can I break long lines when writing c++ code in vim? For example, if I have something like 56 fprintf(stderr, "Syntax error reading recursion value on 57 line %d in file %s\n", line_count, filename); I get the following compile errors: :56:25: warning: missing terminating " character :56: error: missing terminating " character :57: error: stray ‘\’ in program :57:37: warning: missing terminating " character :57: error: missing terminating " character I'm a vim newbie. Thanks!

    Read the article

  • How do I open a file in such a way that if the file doesn't exist it will be created and opened automatically?

    - by snakile
    Here's how I open a file for writing+ : if( fopen_s( &f, fileName, "w+" ) !=0 ) { printf("Open file failed\n"); return; } fprintf_s(f, "content"); If the file doesn't exist the open operation fails. What's the right way to fopen if I want to create the file automatically if the file doesn't already exist? EDIT: If the file does exist, I would like fprintf to overwrite the file, not to append to it.

    Read the article

  • add space to every word's end in a string in C

    - by hlx98007
    Here I have a string: *line = "123 567 890 "; with 2 spaces at the end. I wish to add those 2 spaces to 3's end and 7's end to make it like this: "123 567 890" I was trying to achieve the following steps: parse the string into words by words list (array of strings). From upstream function I will get values of variables word_count, *line and remain. concatenate them with a space at the end. add space distributively, with left to right priority, so when a fair division cannot be done, the second to last word's end will have (no. of spaces) spaces, the previous ones will get (spaces + 1) spaces. concatenate everything together to make it a new *line. Here is a part of my faulty code: int add_space(char *line, int remain, int word_count) { if (remain == 0.0) return 0; // Don't need to operate. int ret; char arr[word_count][line_width]; memset(arr, 0, word_count * line_width * sizeof(char)); char *blank = calloc(line_width, sizeof(char)); if (blank == NULL) { fprintf(stderr, "calloc for arr error!\n"); return -1; } for (int i = 0; i < word_count; i++) { ret = sscanf(line, "%s", arr[i]); // gdb shows somehow it won't read in. if (ret != 1) { fprintf(stderr, "Error occured!\n"); return -1; } arr[i] = strcat(arr[i], " "); // won't compile. } size_t spaces = remain / (word_count * 1.0); memset(blank, ' ', spaces + 1); for (int i = 0; i < word_count - 1; i++) { arr[0] = strcat(arr[i], blank); // won't compile. } memset(blank, ' ', spaces); arr[word_count-1] = strcat(arr[word_count-1], blank); for (int i = 1; i < word_count; i++) { arr[0] = strcat(arr[0], arr[i]); } free(blank); return 0; } It is not working, could you help me find the parts that do not work and fix them please? Thank you guys.

    Read the article

  • matlab's fortran's format equivalents

    - by ldigas
    What would be matlab's equivalent of write(1,'("Speed, resistance, power",3f8.2)')(a(i),i=1,3) I've tried a = [10. 20. 200.] fprintf(unit1,'a = 3%8.1e',a) but I'm still having trouble with it (the whole matlab output formatting thing). Edit for Kenny: for the values of a as given above, it would give (in a new row): Speed, resistance, power 10.00 20.00 200.00

    Read the article

  • Segfault when iterating over a map<string, string> and drawing its contents using SDL_TTF

    - by Michael Stahre
    I'm not entirely sure this question belongs on gamedev.stackexchange, but I'm technically working on a game and working with SDL, so it might not be entirely offtopic. I've written a class called DebugText. The point of the class is to have a nice way of printing values of variables to the game screen. The idea is to call SetDebugText() with the variables in question every time they change or, as is currently the case, every time the game's Update() is called. The issue is that when iterating over the map that contains my variables and their latest updated values, I get segfaults. See the comments in DrawDebugText() below, it specifies where the error happens. I've tried splitting the calls to it-first and it-second into separate lines and found that the problem doesn't always happen when calling it-first. It alters between it-first and it-second. I can't find a pattern. It doesn't fail on every call to DrawDebugText() either. It might fail on the third time DrawDebugText() is called, or it might fail on the fourth. Class header: #ifndef CLIENT_DEBUGTEXT_H #define CLIENT_DEBUGTEXT_H #include <Map> #include <Math.h> #include <sstream> #include <SDL.h> #include <SDL_ttf.h> #include "vector2.h" using std::string; using std::stringstream; using std::map; using std::pair; using game::Vector2; namespace game { class DebugText { private: TTF_Font* debug_text_font; map<string, string>* debug_text_list; public: void SetDebugText(string var, bool value); void SetDebugText(string var, float value); void SetDebugText(string var, int value); void SetDebugText(string var, Vector2 value); void SetDebugText(string var, string value); int DrawDebugText(SDL_Surface*, SDL_Rect*); void InitDebugText(); void Clear(); }; } #endif Class source file: #include "debugtext.h" namespace game { // Copypasta function for handling the toString conversion template <class T> inline string to_string (const T& t) { stringstream ss (stringstream::in | stringstream::out); ss << t; return ss.str(); } // Initializes SDL_TTF and sets its font void DebugText::InitDebugText() { if(TTF_WasInit()) TTF_Quit(); TTF_Init(); debug_text_font = TTF_OpenFont("LiberationSans-Regular.ttf", 16); TTF_SetFontStyle(debug_text_font, TTF_STYLE_NORMAL); } // Iterates over the current debug_text_list and draws every element on the screen. // After drawing with SDL you need to get a rect specifying the area on the screen that was changed and tell SDL that this part of the screen needs to be updated. this is done in the game's Draw() function // This function sets rects_to_update to the new list of rects provided by all of the surfaces and returns the number of rects in the list. These two parameters are used in Draw() when calling on SDL_UpdateRects(), which takes an SDL_Rect* and a list length int DebugText::DrawDebugText(SDL_Surface* screen, SDL_Rect* rects_to_update) { if(debug_text_list == NULL) return 0; if(!TTF_WasInit()) InitDebugText(); rects_to_update = NULL; // Specifying the font color SDL_Color font_color = {0xff, 0x00, 0x00, 0x00}; // r, g, b, unused int row_count = 0; string line; // The iterator variable map<string, string>::iterator it; // Gets the iterator and iterates over it for(it = debug_text_list->begin(); it != debug_text_list->end(); it++) { // Takes the first value (the name of the variable) and the second value (the value of the parameter in string form) //---------THIS LINE GIVES ME SEGFAULTS----- line = it->first + ": " + it->second; //------------------------------------------ // Creates a surface with the text on it that in turn can be rendered to the screen itself later SDL_Surface* debug_surface = TTF_RenderText_Solid(debug_text_font, line.c_str(), font_color); if(debug_surface == NULL) { // A standard check for errors fprintf(stderr, "Error: %s", TTF_GetError()); return NULL; } else { // If SDL_TTF did its job right, then we now set a destination rect row_count++; SDL_Rect dstrect = {5, 5, 0, 0}; // x, y, w, h dstrect.x = 20; dstrect.y = 20*row_count; // Draws the surface with the text on it to the screen int res = SDL_BlitSurface(debug_surface,NULL,screen,&dstrect); if(res != 0) { //Just an error check fprintf(stderr, "Error: %s", SDL_GetError()); return NULL; } // Creates a new rect to specify the area that needs to be updated with SDL_Rect* new_rect_to_update = (SDL_Rect*) malloc(sizeof(SDL_Rect)); new_rect_to_update->h = debug_surface->h; new_rect_to_update->w = debug_surface->w; new_rect_to_update->x = dstrect.x; new_rect_to_update->y = dstrect.y; // Just freeing the surface since it isn't necessary anymore SDL_FreeSurface(debug_surface); // Creates a new list of rects with room for the new rect SDL_Rect* newtemp = (SDL_Rect*) malloc(row_count*sizeof(SDL_Rect)); // Copies the data from the old list of rects to the new one memcpy(newtemp, rects_to_update, (row_count-1)*sizeof(SDL_Rect)); // Adds the new rect to the new list newtemp[row_count-1] = *new_rect_to_update; // Frees the memory used by the old list free(rects_to_update); // And finally redirects the pointer to the old list to the new list rects_to_update = newtemp; newtemp = NULL; } } // When the entire map has been iterated over, return the number of lines that were drawn, ie. the number of rects in the returned rect list return row_count; } // The SetDebugText used by all the SetDebugText overloads // Takes two strings, inserts them into the map as a pair void DebugText::SetDebugText(string var, string value) { if (debug_text_list == NULL) { debug_text_list = new map<string, string>(); } debug_text_list->erase(var); debug_text_list->insert(pair<string, string>(var, value)); } // Writes the bool to a string and calls SetDebugText(string, string) void DebugText::SetDebugText(string var, bool value) { string result; if (value) result = "True"; else result = "False"; SetDebugText(var, result); } // Does the same thing, but uses to_string() to convert the float void DebugText::SetDebugText(string var, float value) { SetDebugText(var, to_string(value)); } // Same as above, but int void DebugText::SetDebugText(string var, int value) { SetDebugText(var, to_string(value)); } // Vector2 is a struct of my own making. It contains the two float vars x and y void DebugText::SetDebugText(string var, Vector2 value) { SetDebugText(var + ".x", to_string(value.x)); SetDebugText(var + ".y", to_string(value.y)); } // Empties the list. I don't actually use this in my code. Shame on me for writing something I don't use. void DebugText::Clear() { if(debug_text_list != NULL) debug_text_list->clear(); } }

    Read the article

  • Library like ENet, but for TCP?

    - by Milo
    I'm not looking to use boost::asio, it is overly complex for my needs. I'm building a game that is cross platform, for desktop, iPhone and Android. I found a library called ENet which is pretty much what I need, but it uses UDP which does not seem to support encryption and a few other things. Given that the game is an event driven card game, TCP seems like the right fit. However, all I have found is WINSOCK / berkley sockets and bost::asio. Here is a sample client server application with ENet: #include <enet/enet.h> #include <stdlib.h> #include <string> #include <iostream> class Host { ENetAddress address; ENetHost * server; ENetHost* client; ENetEvent event; public: Host() :server(NULL) { enet_initialize(); setupServer(); } void setupServer() { if(server) { enet_host_destroy(server); server = NULL; } address.host = ENET_HOST_ANY; /* Bind the server to port 1234. */ address.port = 1721; server = enet_host_create (& address /* the address to bind the server host to */, 32 /* allow up to 32 clients and/or outgoing connections */, 2 /* allow up to 2 channels to be used, 0 and 1 */, 0 /* assume any amount of incoming bandwidth */, 0 /* assume any amount of outgoing bandwidth */); } void daLoop() { while(true) { /* Wait up to 1000 milliseconds for an event. */ while (enet_host_service (server, & event, 5000) > 0) { ENetPacket * packet; switch (event.type) { case ENET_EVENT_TYPE_CONNECT: printf ("A new client connected from %x:%u.\n", event.peer -> address.host, event.peer -> address.port); /* Store any relevant client information here. */ event.peer -> data = "Client information"; /* Create a reliable packet of size 7 containing "packet\0" */ packet = enet_packet_create ("packet", strlen ("packet") + 1, ENET_PACKET_FLAG_RELIABLE); /* Extend the packet so and append the string "foo", so it now */ /* contains "packetfoo\0" */ enet_packet_resize (packet, strlen ("packetfoo") + 1); strcpy ((char*)& packet -> data [strlen ("packet")], "foo"); /* Send the packet to the peer over channel id 0. */ /* One could also broadcast the packet by */ /* enet_host_broadcast (host, 0, packet); */ enet_peer_send (event.peer, 0, packet); /* One could just use enet_host_service() instead. */ enet_host_flush (server); break; case ENET_EVENT_TYPE_RECEIVE: printf ("A packet of length %u containing %s was received from %s on channel %u.\n", event.packet -> dataLength, event.packet -> data, event.peer -> data, event.channelID); /* Clean up the packet now that we're done using it. */ enet_packet_destroy (event.packet); break; case ENET_EVENT_TYPE_DISCONNECT: printf ("%s disconected.\n", event.peer -> data); /* Reset the peer's client information. */ event.peer -> data = NULL; } } } } ~Host() { if(server) { enet_host_destroy(server); server = NULL; } atexit (enet_deinitialize); } }; class Client { ENetAddress address; ENetEvent event; ENetPeer *peer; ENetHost* client; public: Client() :peer(NULL) { enet_initialize(); setupPeer(); } void setupPeer() { client = enet_host_create (NULL /* create a client host */, 1 /* only allow 1 outgoing connection */, 2 /* allow up 2 channels to be used, 0 and 1 */, 57600 / 8 /* 56K modem with 56 Kbps downstream bandwidth */, 14400 / 8 /* 56K modem with 14 Kbps upstream bandwidth */); if (client == NULL) { fprintf (stderr, "An error occurred while trying to create an ENet client host.\n"); exit (EXIT_FAILURE); } /* Connect to some.server.net:1234. */ enet_address_set_host (& address, "192.168.2.13"); address.port = 1721; /* Initiate the connection, allocating the two channels 0 and 1. */ peer = enet_host_connect (client, & address, 2, 0); if (peer == NULL) { fprintf (stderr, "No available peers for initiating an ENet connection.\n"); exit (EXIT_FAILURE); } /* Wait up to 5 seconds for the connection attempt to succeed. */ if (enet_host_service (client, & event, 20000) > 0 && event.type == ENET_EVENT_TYPE_CONNECT) { std::cout << "Connection to some.server.net:1234 succeeded." << std::endl; } else { /* Either the 5 seconds are up or a disconnect event was */ /* received. Reset the peer in the event the 5 seconds */ /* had run out without any significant event. */ enet_peer_reset (peer); puts ("Connection to some.server.net:1234 failed."); } } void daLoop() { ENetPacket* packet; /* Create a reliable packet of size 7 containing "packet\0" */ packet = enet_packet_create ("backet", strlen ("backet") + 1, ENET_PACKET_FLAG_RELIABLE); /* Extend the packet so and append the string "foo", so it now */ /* contains "packetfoo\0" */ enet_packet_resize (packet, strlen ("backetfoo") + 1); strcpy ((char*)& packet -> data [strlen ("backet")], "foo"); /* Send the packet to the peer over channel id 0. */ /* One could also broadcast the packet by */ /* enet_host_broadcast (host, 0, packet); */ enet_peer_send (event.peer, 0, packet); /* One could just use enet_host_service() instead. */ enet_host_flush (client); while(true) { /* Wait up to 1000 milliseconds for an event. */ while (enet_host_service (client, & event, 1000) > 0) { ENetPacket * packet; switch (event.type) { case ENET_EVENT_TYPE_RECEIVE: printf ("A packet of length %u containing %s was received from %s on channel %u.\n", event.packet -> dataLength, event.packet -> data, event.peer -> data, event.channelID); /* Clean up the packet now that we're done using it. */ enet_packet_destroy (event.packet); break; } } } } ~Client() { atexit (enet_deinitialize); } }; int main() { std::string a; std::cin >> a; if(a == "host") { Host host; host.daLoop(); } else { Client c; c.daLoop(); } return 0; } I looked at some socket tutorials and they seemed a bit too low level. I just need something that abstracts away the platform (eg, no WINSOCKS) and that has basic ability to keep track of connected clients and send them messages. Thanks

    Read the article

  • OpenGL: glGetError() returns invalid enum after call to glewInit()

    - by malymato
    I use GLEW and freeglut. For some reason, after a call to glewInit(), glGetError() returns error code 1280. Reinstalling the drivers didn't help. I tried to disable glewExperimental, it had no effect. Code worked before, but I am not aware of any changes I could possibly make. Here's my code: int main(int argc, char* argv[]) { GLenum GlewInitResult, res; InitWindow(argc, argv); res = glGetError(); // res = 0 glewExperimental = GL_TRUE; GlewInitResult = glewInit(); res = glGetError(); // res = 1280 glutMainLoop(); exit(EXIT_SUCCESS); } void InitWindow(int argc, char* argv[]) { glutInit(&argc, argv); glutInitContextVersion(4, 0); glutInitContextFlags(GLUT_FORWARD_COMPATIBLE); glutInitContextProfile(GLUT_CORE_PROFILE); glutSetOption(GLUT_ACTION_ON_WINDOW_CLOSE, GLUT_ACTION_GLUTMAINLOOP_RETURNS); glutInitWindowPosition(0, 0); glutInitWindowSize(CurrentWidth, CurrentHeight); glutInitDisplayMode(GLUT_DEPTH | GLUT_DOUBLE | GLUT_RGBA); WindowHandle = glutCreateWindow(WINDOW_TITLE); GLenum errorCheckValue = glGetError(); if (WindowHandle < 1) { fprintf(stderr, "ERROR: Could not create new rendering window.\n"); exit(EXIT_FAILURE); } glutReshapeFunc(ResizeFunction); glutDisplayFunc(RenderFunction); glutIdleFunc(IdleFunction); glutTimerFunc(0, TimerFunction, 0); glutCloseFunc(Cleanup); glutKeyboardFunc(KeyboardFunction); } Could someone tell me what I am doing wrong? Thanks.

    Read the article

  • Concurrency pattern of logger in multithreaded application

    - by Dipan Mehta
    The context: We are working on a multi-threaded (Linux-C) application that follows a pipeline model. Each module has a private thread and encapsulated objects which do processing of data; and each stage has a standard form of exchanging data with next unit. The application is free from memory leak and is threadsafe using locks at the point where they exchange data. Total number of threads is about 15- and each thread can have from 1 to 4 objects. Making about 25 - 30 odd objects which all have some critical logging to do. Most discussion I have seen about different levels as in Log4J and it's other translations. The real big questions is about how the overall logging should really happen? One approach is all local logging does fprintf to stderr. The stderr is redirected to some file. This approach is very bad when logs become too big. If all object instantiate their individual loggers - (about 30-40 of them) there will be too many files. And unlike above, one won't have the idea of true order of events. Timestamping is one possibility - but it is still a mess to collate. If there is a single global logger (singleton) pattern - it indirectly blocks so many threads while one is busy putting up logs. This is unacceptable when processing of the threads are heavy. So what should be the ideal way to structure the logging objects? What are some of the best practices in actual large scale applications? I would also love to learn from some of the real designs of large scale applications to get inspirations from!

    Read the article

  • multiple timer to one process (without linking to rt)

    - by Richard
    Hi, is there any way to register multiple timer to a single process? I have tried following code, yet without success. (Use "gcc -lrt" to compile it...). Program output nothing, which should atleast print "test". Is it possibly due to the dependence to linking to rt? #define TT_SIGUSR1 (SIGRTMAX) #define TT_SIGUSR2 (SIGRTMAX - 1) #define TIME_INTERVAL_1 1 #define TIME_INTERVAL_2 2 #include <signal.h> #include <time.h> #include <stdio.h> #include <unistd.h> #include <linux/unistd.h> #include <sys/syscall.h> #include <sys/time.h> #include <sys/types.h> #include <sched.h> #include <signal.h> #include <setjmp.h> #include <errno.h> #include <assert.h> timer_t create_timer(int signo) { timer_t timerid; struct sigevent se; se.sigev_signo = signo; if (timer_create(CLOCK_REALTIME, &se, &timerid) == -1) { fprintf(stderr, "Failed to create timer\n"); exit(-1); } return timerid; } void set_timer(timer_t timerid, int seconds) { struct itimerspec timervals; timervals.it_value.tv_sec = seconds; timervals.it_value.tv_nsec = 0; timervals.it_interval.tv_sec = seconds; timervals.it_interval.tv_nsec = 0; if (timer_settime(timerid, 0, &timervals, NULL) == -1) { fprintf(stderr, "Failed to start timer\n"); exit(-1); } return; } void install_sighandler2(int signo, void(*handler)(int)) { struct sigaction sigact; sigemptyset(&sigact.sa_mask); sigact.sa_flags = SA_SIGINFO; //register the Signal Handler sigact.sa_sigaction = handler; // Set up sigaction to catch signal first timer if (sigaction(signo, &sigact, NULL) == -1) { printf("sigaction failed"); return -1; } } void install_sighandler(int signo, void(*handler)(int)) { sigset_t set; struct sigaction act; /* Setup the handler */ act.sa_handler = handler; act.sa_flags = SA_RESTART; sigaction(signo, &act, 0); /* Unblock the signal */ sigemptyset(&set); sigaddset(&set, signo); sigprocmask(SIG_UNBLOCK, &set, NULL); return; } void signal_handler(int signo) { printf("receiving sig %d", signo); } int main() { printf("test"); timer_t timer1 = create_timer(TT_SIGUSR1); timer_t timer2 = create_timer(TT_SIGUSR2); set_timer(timer1, TIME_INTERVAL_1); set_timer(timer2, TIME_INTERVAL_2); install_sighandler2(TT_SIGUSR1, signal_handler); install_sighandler(TT_SIGUSR2, signal_handler); while (1) ; return 0; }

    Read the article

  • "assignment makes integer from pointer without a cast " warning in c

    - by mekasperasky
    #include<stdio.h> /* this is a lexer which recognizes constants , variables ,symbols, identifiers , functions , comments and also header files . It stores the lexemes in 3 different files . One file contains all the headers and the comments . Another file will contain all the variables , another will contain all the symbols. */ int main() { int i=0,j; char a,b[20],c[30]; FILE *fp1,*fp2; c[0]='"if"; c[1]="then"; c[2]="else"; c[3]="switch"; c[4]="printf"; c[5]="scanf"; c[6]="NULL"; c[7]="int"; c[8]="char"; c[9]="float"; c[10]="long"; c[11]="double"; c[12]="char"; c[13]="const"; c[14]="continue"; c[15]="break"; c[16]="for"; c[17]="size of"; c[18]="register"; c[19]="short"; c[20]="auto"; c[21]="while"; c[22]="do"; c[23]="case"; fp1=fopen("source.txt","r"); //the source file is opened in read only mode which will passed through the lexer fp2=fopen("lext.txt","w"); //now lets remove all the white spaces and store the rest of the words in a file if(fp1==NULL) { perror("failed to open source.txt"); //return EXIT_FAILURE; } i=0; while(!feof(fp1)) { a=fgetc(fp1); if(a!=' ') { b[i]=a; } else { for (j=0;j<23;j++) { if(c[j]==b) { fprintf(fp2, "%.20s\n", c[j]); continue ; } b[i]='\0'; fprintf(fp2, "%.20s\n", b); i=0; continue; } //else if //{ i=i+1; /*Switch(a) { case EOF :return eof; case '+':sym=sym+1; case '-':sym=sym+1; case '*':sym=sym+1; case '/':sym=sym+1; case '%':sym=sym+1; case ' */ } fclose(fp1); fclose(fp2); return 0; } This is my c code for lexical analysis .. its giving warnings and also not writing anything into the lext file ..

    Read the article

  • about getadrrinfo() C++?

    - by Isavel
    I'm reading this book called beej's guide to network programming and there's a part in the book were it provide a sample code which illustrate the use of getaddrinfo(); the book state that the code below "will print the IP addresses for whatever host you specify on the command line" - beej's guide to network programming. now I'm curious and want to try it out and run the code, but I guess the code was develop in UNIX environment and I'm using visual studio 2012 windows 7 OS, and most of the headers was not supported so I did a bit of research and find out that I need to include the winsock.h and ws2_32.lib for windows, for it to get working, fortunately everything compiled no errors, but when I run it using the debugger and put in 'www.google.com' as command argument I was disappointed that it did not print any ipaddress, the output that I got from the console is "getaddrinfo: E" what does the letter E mean? Do I need to configure something out of the debugger? Interestingly I left the command argument blank and the output changed to "usage: showip hostname" Any help would be appreciated. #ifdef _WIN32 #endif #include <sys/types.h> #include <winsock2.h> #include <ws2tcpip.h> #include <iostream> using namespace std; #include <stdio.h> #include <string.h> #include <sys/types.h> #include <winsock.h> #pragma comment(lib, "ws2_32.lib") int main(int argc, char *argv[]) { struct addrinfo hints, *res, *p; int status; char ipstr[INET6_ADDRSTRLEN]; if (argc != 2) { fprintf(stderr,"usage: showip hostname\n"); system("PAUSE"); return 1; } memset(&hints, 0, sizeof hints); hints.ai_family = AF_UNSPEC; // AF_INET or AF_INET6 to force version hints.ai_socktype = SOCK_STREAM; if ((status = getaddrinfo(argv[1], NULL, &hints, &res)) != 0) { fprintf(stderr, "getaddrinfo: %s\n", gai_strerror(status)); system("PAUSE"); return 2; } printf("IP addresses for %s:\n\n", argv[1]); for(p = res;p != NULL; p = p->ai_next) { void *addr; char *ipver; // get the pointer to the address itself, // different fields in IPv4 and IPv6: if (p->ai_family == AF_INET) { // IPv4 struct sockaddr_in *ipv4 = (struct sockaddr_in *)p->ai_addr; addr = &(ipv4->sin_addr); ipver = "IPv4"; } else { // IPv6 struct sockaddr_in6 *ipv6 = (struct sockaddr_in6 *)p->ai_addr; addr = &(ipv6->sin6_addr); ipver = "IPv6"; } // convert the IP to a string and print it: inet_ntop(p->ai_family, addr, ipstr, sizeof ipstr); printf(" %s: %s\n", ipver, ipstr); } freeaddrinfo(res); // free the linked list system("PAUSE"); return 0; }

    Read the article

  • how to clear stack after stack overflow signal occur

    - by user353573
    In pthread, After reaching yellow zone in stack, signal handler stop the recursive function by making it return however, we can only continue to use extra area in yellow zone, how to clear the rubbish before the yellow zone in the thread stack ? (Copied from "answers"): #include <pthread.h> #include <stdio.h> #include <stdlib.h> #include <signal.h> #include <setjmp.h> #include <sys/mman.h> #include <unistd.h> #include <assert.h> #include <sys/resource.h> #define ALT_STACK_SIZE (64*1024) #define YELLOW_ZONE_PAGES (1) typedef struct { size_t stack_size; char* stack_pointer; char* red_zone_boundary; char* yellow_zone_boundary; sigjmp_buf return_point; size_t red_zone_size; } ThreadInfo; static pthread_key_t thread_info_key; static struct sigaction newAct, oldAct; bool gofromyellow = false; int call_times = 0; static void main_routine(){ // make it overflow if(gofromyellow == true) { printf("return from yellow zone, called %d times\n", call_times); return; } else { call_times = call_times + 1; main_routine(); gofromyellow = true; } } // red zone management static void stackoverflow_routine(){ fprintf(stderr, "stack overflow error.\n"); fflush(stderr); } // yellow zone management static void yellow_zone_hook(){ fprintf(stderr, "exceed yellow zone.\n"); fflush(stderr); } static int get_stack_info(void** stackaddr, size_t* stacksize){ int ret = -1; pthread_attr_t attr; pthread_attr_init(&attr); if(pthread_getattr_np(pthread_self(), &attr) == 0){ ret = pthread_attr_getstack(&attr, stackaddr, stacksize); } pthread_attr_destroy(&attr); return ret; } static int is_in_stack(const ThreadInfo* tinfo, char* pointer){ return (tinfo->stack_pointer <= pointer) && (pointer < tinfo->stack_pointer + tinfo->stack_size); } static int is_in_red_zone(const ThreadInfo* tinfo, char* pointer){ if(tinfo->red_zone_boundary){ return (tinfo->stack_pointer <= pointer) && (pointer < tinfo->red_zone_boundary); } } static int is_in_yellow_zone(const ThreadInfo* tinfo, char* pointer){ if(tinfo->yellow_zone_boundary){ return (tinfo->red_zone_boundary <= pointer) && (pointer < tinfo->yellow_zone_boundary); } } static void set_yellow_zone(ThreadInfo* tinfo){ int pagesize = sysconf(_SC_PAGE_SIZE); assert(pagesize > 0); tinfo->yellow_zone_boundary = tinfo->red_zone_boundary + pagesize * YELLOW_ZONE_PAGES; mprotect(tinfo->red_zone_boundary, pagesize * YELLOW_ZONE_PAGES, PROT_NONE); } static void reset_yellow_zone(ThreadInfo* tinfo){ size_t pagesize = tinfo->yellow_zone_boundary - tinfo->red_zone_boundary; if(mmap(tinfo->red_zone_boundary, pagesize, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, 0, 0) == 0){ perror("mmap failed"), exit(1); } mprotect(tinfo->red_zone_boundary, pagesize, PROT_READ | PROT_WRITE); tinfo->yellow_zone_boundary = 0; } static void signal_handler(int sig, siginfo_t* sig_info, void* sig_data){ if(sig == SIGSEGV){ ThreadInfo* tinfo = (ThreadInfo*) pthread_getspecific(thread_info_key); char* fault_address = (char*) sig_info->si_addr; if(is_in_stack(tinfo, fault_address)){ if(is_in_red_zone(tinfo, fault_address)){ siglongjmp(tinfo->return_point, 1); }else if(is_in_yellow_zone(tinfo, fault_address)){ reset_yellow_zone(tinfo); yellow_zone_hook(); gofromyellow = true; return; } else { //inside stack not related overflow SEGV happen } } } } static void register_application_info(){ pthread_key_create(&thread_info_key, NULL); sigemptyset(&newAct.sa_mask); sigaddset(&newAct.sa_mask, SIGSEGV); newAct.sa_sigaction = signal_handler; newAct.sa_flags = SA_SIGINFO | SA_RESTART | SA_ONSTACK; sigaction(SIGSEGV, &newAct, &oldAct); } static void register_thread_info(ThreadInfo* tinfo){ stack_t ss; pthread_setspecific(thread_info_key, tinfo); get_stack_info((void**)&tinfo->stack_pointer, &tinfo->stack_size); printf("stack size %d mb\n", tinfo->stack_size/1024/1024 ); tinfo->red_zone_boundary = tinfo->stack_pointer + tinfo->red_zone_size; set_yellow_zone(tinfo); ss.ss_sp = (char*)malloc(ALT_STACK_SIZE); ss.ss_size = ALT_STACK_SIZE; ss.ss_flags = 0; sigaltstack(&ss, NULL); } static void* thread_routine(void* p){ ThreadInfo* tinfo = (ThreadInfo*)p; register_thread_info(tinfo); if(sigsetjmp(tinfo->return_point, 1) == 0){ main_routine(); } else { stackoverflow_routine(); } free(tinfo); printf("after tinfo, end thread\n"); return 0; } int main(int argc, char** argv){ register_application_info(); if( argc == 2 ){ int stacksize = atoi(argv[1]); pthread_attr_t attr; pthread_attr_init(&attr); pthread_attr_setstacksize(&attr, 1024 * 1024 * stacksize); { pthread_t pid0; ThreadInfo* tinfo = (ThreadInfo*)calloc(1, sizeof(ThreadInfo)); pthread_attr_getguardsize(&attr, &tinfo->red_zone_size); pthread_create(&pid0, &attr, thread_routine, tinfo); pthread_join(pid0, NULL); } } else { printf("Usage: %s stacksize(mb)\n", argv[0]); } return 0; } C language in linux, ubuntu

    Read the article

  • How to read STDIN into string variable until EOF in C?

    - by NovumCoder
    Hi, im getting "Bus Error" trying to read stdin into a char* variable. I just want to read whole stuff coming over stdin and put it first into a variable, then continue working on the variable. My Code is as follows: char* content; char* c; while( scanf( "%c", c)) { strcat( content, c); } fprintf( stdout, "Size: %d", strlen( content)); But somehow i always get "Bus error" returned by calling "cat test.txt | myapp", where "myapp" is the compiled code above. My question is how do i read stdin until EOF into a variable? As you see in the code, i just want to print the size of input coming over stdin, in this case it should be equal to the size of the file "test.txt". I thought just using scanf would be enough, maybe buffered way to read stdin?

    Read the article

  • InternetReadFile() corrupting donwloads C

    - by Lienau
    I'm able to download text documents (.html, .txt, etc) but I can't download images or exe's. I'm pretty sure that this is because I'm using a char, and thoes files are binary. I know that in C# I would use a byte. But what data-type would I use in this case? char buffer[1]; DWORD dwRead; FILE * pFile; pFile = fopen(file,"w"); while (InternetReadFile(hRequest, buffer, 1, &dwRead)) { if(dwRead != 1) break; fprintf(pFile,"%s",buffer); } fclose(pFile);

    Read the article

  • MATLAB how to write header in text file

    - by Jessy
    How to write a text header in text file? for example in the example below, how to write the header code salay month just once? Code Salary Month 12 1000 12 14 1020 11 11 1212 9 fid = fopen('analysis1.txt','wt'); for i=1:10 array = []; % empty the array .... array = [code salary month]; format short g; fprintf(fid,'%g\t %g\t %g\n',array); % write to file end fclose(fid);

    Read the article

  • Ajax based progress bar

    - by Punit
    I am developing a progress bar using Ajax. My client side code is working fine, but I have issue at server side. I am using C based CGI. if(i == inc && pb_inc<=100) { fptr = fopen("progress_bar.txt", "w"); fprintf(fptr,"%d", j); fclose(fptr); pb_inc++; } basically I am increasing progress bar after certain number of bytes. What I see here is that the CGI doesn't let display any data to text file until it has sent all the data to file one by one. i have referred to http://www.redips.net/javascript/ajax-progress-bar/ Any idea whats happening here?

    Read the article

  • Unknown error in Producer/Consumer program, believe it to be an infinite loop.

    - by ray2k
    Hello, I am writing a program that is solving the producer/consumer problem, specifically the bounded-buffer version(i believe they mean the same thing). The producer will be generating x number of random numbers, where x is a command line parameter to my program. At the current moment, I believe my program is entering an infinite loop, but I'm not sure why it is occurring. I believe I am executing the semaphores correctly. You compile it like this: gcc -o prodcon prodcon.cpp -lpthread -lrt Then to run, ./prodcon 100(the number of randum nums to produce) This is my code. typedef int buffer_item; #include <stdlib.h> #include <stdio.h> #include <pthread.h> #include <semaphore.h> #include <unistd.h> #define BUFF_SIZE 10 #define RAND_DIVISOR 100000000 #define TRUE 1 //two threads void *Producer(void *param); void *Consumer(void *param); int insert_item(buffer_item item); int remove_item(buffer_item *item); int returnRandom(); //the global semaphores sem_t empty, full, mutex; //the buffer buffer_item buf[BUFF_SIZE]; //buffer counter int counter; //number of random numbers to produce int numRand; int main(int argc, char** argv) { /* thread ids and attributes */ pthread_t pid, cid; pthread_attr_t attr; pthread_attr_init(&attr); pthread_attr_setscope(&attr, PTHREAD_SCOPE_SYSTEM); numRand = atoi(argv[1]); sem_init(&empty,0,BUFF_SIZE); sem_init(&full,0,0); sem_init(&mutex,0,0); printf("main started\n"); pthread_create(&pid, &attr, Producer, NULL); pthread_create(&cid, &attr, Consumer, NULL); printf("main gets here"); pthread_join(pid, NULL); pthread_join(cid, NULL); printf("main done\n"); return 0; } //generates a randum number between 1 and 100 int returnRandom() { int num; srand(time(NULL)); num = rand() % 100 + 1; return num; } //begin producing items void *Producer(void *param) { buffer_item item; int i; for(i = 0; i < numRand; i++) { //sleep for a random period of time int rNum = rand() / RAND_DIVISOR; sleep(rNum); //generate a random number item = returnRandom(); //acquire the empty lock sem_wait(&empty); //acquire the mutex lock sem_wait(&mutex); if(insert_item(item)) { fprintf(stderr, " Producer report error condition\n"); } else { printf("producer produced %d\n", item); } /* release the mutex lock */ sem_post(&mutex); /* signal full */ sem_post(&full); } return NULL; } /* Consumer Thread */ void *Consumer(void *param) { buffer_item item; int i; for(i = 0; i < numRand; i++) { /* sleep for a random period of time */ int rNum = rand() / RAND_DIVISOR; sleep(rNum); /* aquire the full lock */ sem_wait(&full); /* aquire the mutex lock */ sem_wait(&mutex); if(remove_item(&item)) { fprintf(stderr, "Consumer report error condition\n"); } else { printf("consumer consumed %d\n", item); } /* release the mutex lock */ sem_post(&mutex); /* signal empty */ sem_post(&empty); } return NULL; } /* Add an item to the buffer */ int insert_item(buffer_item item) { /* When the buffer is not full add the item and increment the counter*/ if(counter < BUFF_SIZE) { buf[counter] = item; counter++; return 0; } else { /* Error the buffer is full */ return -1; } } /* Remove an item from the buffer */ int remove_item(buffer_item *item) { /* When the buffer is not empty remove the item and decrement the counter */ if(counter > 0) { *item = buf[(counter-1)]; counter--; return 0; } else { /* Error buffer empty */ return -1; } }

    Read the article

  • SQLITE basic syntax

    - by Doori Bar
    I seem to misunderstand a basic syntax, why this sample works: sqlite3_prepare_v2(db, "insert into test values('boo','boo',0);", strlen(querystring)+1 , &stmt, NULL); if ((rc = sqlite3_step(stmt)) != SQLITE_DONE) fprintf(stderr, "Error: sqlite3_step() %d. Error Message %s;\n",rc,sqlite3_errmsg(db)); But when I try this query: "insert into test(strtest) values('boo');" I get an error: Error: sqlite3_step() 19. Error Message constraint failed; What am I missing? table test is: "create table test (blobtest BLOB(4) NOT NULL, strtest VARCHAR NOT NULL, inttest INTEGER NOT NULL );" Thanks, Doori Bar

    Read the article

  • Removing trailing newline character from fgets() input

    - by sfactor
    i am trying to get some data from the user and send it to another function in gcc. the code is something like this. printf("Enter your Name: "); if(!(fgets(Name, sizeof Name, stdin) != NULL)) { fprintf(stderr, "Error reading Name.\n"); exit(1); } However, i find that it has an \n character in the end. so if i enter John it ends up sending John\n. so how do i remove that \n and send a proper string.

    Read the article

  • InternetReadFile() corrupting downloads in C

    - by Lienau
    I'm able to download text documents (.html, .txt, etc) but I can't download images or exe's. I'm pretty sure that this is because I'm using a char, and those files are binary. I know that in C# I would use a byte. But what data-type would I use in this case? char buffer[1]; DWORD dwRead; FILE * pFile; pFile = fopen(file,"w"); while (InternetReadFile(hRequest, buffer, 1, &dwRead)) { if(dwRead != 1) break; fprintf(pFile,"%s",buffer); } fclose(pFile);

    Read the article

  • lua string printing

    - by anon
    In C, I have format strings, something like: char *msg = "wlll you marry me" fprintf(stderr, "%s, %s?", name, msg); Now, can I do something similar in lua with format strings? I.e. I want something functionally equivalent to: name .. ", " .. msg .. "?" but not so ugly, in lua. Okay, so I can do string.format("%s, %s?", name, msg), but can I go even a step further, something like perl style, where I can go: "%name, %msg?" Thanks!

    Read the article

  • trivial linux sound playback

    - by anon
    The classical C program is something like: int main() { fprintf(stderr, "hello world\n"); } a classical OpenGL program is: open up a window setup ortho view draw a colored triangle Now, I want to do the most basic thing for sound in Linux. I want to: 1) open up speakers 2) send a bunch of data, meant to be interpreted at 40Khz, 3) have pseakers play said data no midi, no instruments, ... just playing back raw data What is the easiest way to do this in a C program? [and what libraries; what's the equiv to OpenGL for sound?] Thanks!

    Read the article

  • How to debug/reformat C printf calls with lots of arguments in vim?

    - by Costi
    I have a function call in a program that I'm maintaining has 28 arguments for a printf call. It's printing a lot of data in a CSV file. I have problems following finding where what goes and I have some mismatches in the parameters types. I enabled -Wall in gcc and I get warnings like: n.c:495: warning: int format, pointer arg (arg 15) n.c:495: warning: format argument is not a pointer (arg 16) n.c:495: warning: double format, pointer arg (arg 23) The function is like this: fprintf (ConvFilePtr, "\"FORMAT3\"%s%04d%s%04d%s%s%s%d%s%c%s%d%c%s%s%s%s%s%s%s%11.lf%s%11.lf%s%11.lf%s%d\n", some_28_arguments_go_here); I would like to know if there is a vim plugin that highlights the printf format specifier when i go with the cursor over a variable. Other solutions? How to better reformat the code to make it more readable?

    Read the article

< Previous Page | 2 3 4 5 6 7 8 9 10  | Next Page >