Hidden segfaults

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Original post by wendigo23 It's impossible to tell without seeing the data files that are being read. Even then, it may be impossible to tell without see the rest of the game's source code. How are you sure it's in this code? There are other problems lurking in this code. You're loading the tile's every time they're drawn, for example. You should load them once somewhere besides the drawing function.

WALL = 10 - 10 - 0 - resources/sprites/church_floor.bmpWALL = 10 - 10 - 0 - resources/sprites/church_floor.bmp

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Original post by jyk I assume this is C++? If so, it looks like you're basically programming in C (or what we sometimes call 'C with classes'). C++ is a low-level language, but C is lower-level still, and C (or C-ish) code is often replete with opportunities for access violations, segfaults, and other unpleasant behavior. Every fixed-sized buffer, every call to strcpy(), every argument passed via pointer - each is an opportunity for nasty bugs to arise. C++ is by no means an easy language to program in, but it is much easier to avoid these types of errors in C++, assuming you write idiomatic code and use the tools that the language provides. In your case, for example, replacing character buffers, C-style file access, and raw arrays with string objects, file stream objects, and range-checked containers such as vector or boost::multi_array would go a long way towards making your code safer, more robust, and less error-prone.

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Original post by archaos90 To my experience, the string-class generally never works and almost always makes my program crash where a char array works perfectly.

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Almost everything C++ and whatever it's STL brings, brings nothing more than trouble.

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Original post by archaos90 To my experience, the string-class generally never works and almost always makes my program crash where a char array works perfectly. Almost everything C++ and whatever it's STL brings, brings nothing more than trouble.

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Original post by jyk Your basic implementation of the basic_string class template (such as those provided along with GCC or VC++) should be, for all practical purposes, bug-free. As such, it's safe to say that the string class works fine. If you found that it always made your program crash, it was most likely that you were using it incorrectly. (There aren't that many ways to screw up when using string objects, but it's still possible - for example, by reading or writing past the end of its allocated buffer.)

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Original post by archaos90 char spritefile[50]; public: Room(const char *file); void LoadRoom(const char *file);Room::Room(const char *file)void Room::LoadRoom(const char *file) FILE *roomfile; char sprfile[50]; roomfile = fopen(file, "r"); char tag[20]; char params[100]; while(fscanf(roomfile, "%s = %s", tag, params) != EOF) if (strcmp(tag, "WALL") == 0) sscanf(params, "%d - %d - %d - %s", &posx, &posy, &pass, sprfile); strcpy(rmap[posy][posx].spritefile, sprfile); else if (strcmp(tag, "COMMENT") == 0)

#include <string>#include <fstream>#include <sstream>#include <map>struct Sector {  int posx;  int posy;                          std::string spritefile;  bool passable;};std::map<std::string, SDL_Surface*> sprite_mapping;struct Room {  Room(const std::string& filename);  void Draw(SDL_Surface *to);  int rootx;  int rooty;  Sector rmap[100][100];                                                                     };Room::Room(const std::string& filename) {                                ifstream file(filename.c_str()); // the "open" is implicit.  std::string line;  while (std::getline(file, line)) {    // There's this other thing that also exists in C called    // "scoping your variables properly"...    std::stringstream ss(line); // what we use to "re-parse" data.    // Instead of having a whole suite of s* functions that mirror the f*    // file I/O, we simply make a different kind of stream (from the string),    // and then forget it's anything different at all. Polymorphism!    std::string tag;    char equals;    ss >> tag >> equals;    if (equals == '=' && tag == "WALL") { // Yes, you really can compare strings just like that!            // We can avoid repeating ourselves, with a reference:      Sector& s = rmap[posy][posx];      // Yes, we use it like a value, even though it's not a copy...       // ... and we can read directly into its members instead of temporaries:      ss >> s.posx >> s.posy >> s.pass >> s.spritefile;      // Notice how we read into a bool, too. There's no magic format specifier      // for that.      // While we're at it, let's do that loading:      std::string& name = s.spritefile;      if (sprite_mapping.find(name) == sprite_mapping.end()) {        SDL_Surface* sprite = SDL_LoadBMP(name);        SDL_SetColorKey(sprite, SDL_SRCCOLORKEY,                         SDL_MapRGB(sprite->format, 0x00, 0x00, 0xFF));        sprite_mapping[name] = sprite;      } // Otherwise, it was already loaded.    }  }}void Room::Draw(SDL_Surface *surface) {  SDL_Rect pos;  // C++ also lets you declare a counter variable directly in the for loop.  // I think C99 does, too.  for (int i2 = 0; i2 < 100; ++i2) {    for (int i = 0; i < 100; ++i) { // spaces are your friends...      const int TILESIZE = 50; // as are constants.      Sector& s = rmap[i2];      pos.x = s.posx * TILESIZE;      pos.y = s.posy * TILESIZE;      pos.w = TILESIZE;      pos.h = TILESIZE;      std::map<std::string, SDL_Surface*>::iterator it = sprite_mapping.find(s.spritefile);      if (it != sprite_mapping.end()) {        SDL_Surface* sprite = it->second;        SDL_BlitSurface(sprite, &sprite->clip_rect, surface, &pos);      }    }  }}

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Original post by Zahlman Quote: Original post by archaos90 char spritefile[50]; public: Room(const char *file); void LoadRoom(const char *file);Room::Room(const char *file)void Room::LoadRoom(const char *file) FILE *roomfile; char sprfile[50]; roomfile = fopen(file, "r"); char tag[20]; char params[100]; while(fscanf(roomfile, "%s = %s", tag, params) != EOF) if (strcmp(tag, "WALL") == 0) sscanf(params, "%d - %d - %d - %s", &posx, &posy, &pass, sprfile); strcpy(rmap[posy][posx].spritefile, sprfile); else if (strcmp(tag, "COMMENT") == 0) With code like this, I'm not surprised you have a segfault somewhere. I understand from things like the keyword 'class' that you are trying to write in this new-fangled language called "C++". Have you heard that we have this class that represents a string, called std::string, and a whole new I/O system built on "streams" which are type-safe and work seamlessly with user-defined types? No? Well, the language was only most recently standardized about ten years ago, so... Not to mention, there is normally no point in factoring out a constructor's work to a separate function like that (don't "reset" a room, just construct another one), no point in an empty else-if block, and it's trivial to convert an integer to a boolean without conditional logic. It's also strange to include "Room" in the name of "Room"'s member functions - do you put wallet money in your wallet? Oh, and a "class" that has everything public is simply a "struct"; C++ does not distinguish those except for private/public considerations. Oh, and you probably don't want to load the image from the hard drive, every time you draw each tile of the room. Instead, make an associative mapping of sprite file names to the loaded contents. This means you only open each file once. Fortunately, C++ makes this easy, with another helpful gadget called std::map. *** Source Snippet Removed *** Of course, it's quite possible that your real problem is that you don't actually have 10,000 Sectors to read in from your file, and therefore you try to draw Sectors that aren't properly set up. The code illustrated will neatly sidestep that (although you will probably run into other issues), by simply trying to find an empty-string spritefile name (because the std::string will get default-constructed, while a char[50] buffer will simply be left to contain whatever was already there in memory), observing that we don't have a corresponding SDL_Surface* loaded, and skipping that Sector.

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Original post by LackOfGrace ever checked the documentation about std::string? checkout std::string::c_str() ( spoiler! it will return a pointer to a char array ) ( you also have .data() wich will give you another type of pointer )