C：打开的文件太多

Question

This code opens a directory, and for every file in the directory it loops through every line of data inside the file, and then parses it to do some calculations and outputs the resulting data into a new file.

The problem is that I can only output a maximum of around 1021 files. I'm closing all of the fopens after outputting all the data, so I'm not sure what I'm doing wrong.

Shouldn't fclose() be closing the open files therefore this not happening?

int main(int argc, char *argv[])
{

 //sample data values
  double lat;
  double lon;  
  double convergence;   
  double pt_scale;        
  int    zone = 54;              
  double major_axis = 6378137.0000;        
  double flattening = (1/298.2572);        
  double zoneWidth = 6;         
  double centMeridian = -177;      
  double falseEast = FALSE_EASTING;         
  double falseNorth = FALSE_NORTHING;
  double scale = SCALE_FACTOR;  

  int max_size = 128;
  int current_size = max_size;
  char *pathStr = malloc(max_size);
  char *outPathStr = malloc(max_size);
  char coData[100]; //max length of line;
  long firstTerm, secondTerm; //terms we will split the line into, lat, lon, elevation.
  int counter = 0; //pos counter
  int d = EOF; //end of file ASCII
  char strIn[200];
  char* elevation;
  char strOut[200];
  char dirOut[200]; //sprintf must use a actual defined buffer otherwise there will be a buffer overflow.
  char* cchr;
  int j;
  _setmaxstdio(2048);
  printf("Please enter the path of the files: \n");
  getUserInput(pathStr, current_size, max_size); 
  printf("Please enter the output path of the files: \n");
  getUserInput(outPathStr, current_size, max_size);
  //loop through each file in the directory. Open the file, convert, then close it.
  //we will use dirent.h as it is cross platform so we wont have to worry about sharing issues
  DIR *dir; //new directory
  struct dirent *ent;
  dir = opendir(pathStr); //allcate it a path
  if(opendir(pathStr) == NULL)
  { printf("Error: %d (%s)\n", errno, strerror(errno));}
  int k;

  if(dir != NULL)
  {

         while((ent = readdir(dir)) != NULL) //loop through each file in the directory.
         {
                    //open the file and loop through each line converting it then outputing it into a new file
                if((!strcmp(ent->d_name,"..") || !strcmp(ent->d_name,".")) == 1)
                {
                        //dont want these directories
                        continue;
                }
                else
                {
                sprintf(strIn,"%s%s",pathStr,ent->d_name);    //get the file n
                FILE *fp = fopen(strIn, "r");
                if(fopen(strIn, "r") == NULL) //for inputting file
                { printf("Error: %d (%s)\n", errno, strerror(errno));
                                getchar();
                                  break; }

                sprintf(dirOut,"%s%d%s",outPathStr,counter,".geo");
                printf("%s \n",dirOut);
                FILE *fp2 = fopen(dirOut, "w"); //for outputting file
                if(fopen(dirOut, "w") == NULL)
                     { printf("Error: %d (%s)\n", errno, strerror(errno));
                      getchar();
                      break; }


                     while(fgets(coData, 100, fp) != NULL)//loop through line by line, allocate into 2 doubles and a string, pass the two coordinates and convert
                     {
                        //extract terms from coData                
                        char * pch; //pointer to array pos
                        char * pend;                          
                        pch = strtok(coData," ");                          
                        j = 0;

                            while(j <= 2) //We only want to split the first three parameters.
                            {
                                    //convert char array to double for co-oridinate conversion  

                                    if(j == 0)
                                    {
                                    firstTerm = atof(pch);         //latitude;           
                                    j++;
                                    continue;
                                    }
                                    if(j == 1)
                                    {
                                    pch = strtok(NULL, " ");
                                    secondTerm = atof(pch); //longitude
                                    j++;
                                    continue;
                                    }
                                    if(j == 2)
                                    {
                                    pch = strtok(NULL," ");
                                    elevation = pch; //elevation doesnt need to be converted because it isnt used in the coordinate conversion.
                                    break;
                                    }                                                               
                            }
                       grid2spheroid(&lat,&lon,&convergence,&pt_scale,firstTerm,secondTerm,zone,0, major_axis,flattening,zoneWidth,centMeridian,falseEast,falseNorth,scale);                                            
                       sprintf(strOut,"%f %f %s",lat,lon,elevation);
                       //printf("%d %d", lat, lon);                          
                       fputs(strOut,fp2);


                     }     //end of while        

                      fclose(fp2);
                      fclose(fp);
                      counter++;
                 }

                }
                closedir(dir);
  }
  free(pathStr); //finished using the path string so we can finish the 
  free(outPathStr);
  getchar(); 
  return 0;

 }

  void getUserInput(char *pathStr, int current_size, int max_size)
 {
 unsigned int i = 0;
 if(pathStr != NULL)
  {
              int c = EOF;

              //get the user input and reallocate the memory size if the input it too large.
              while((c = getchar()) != '\n' && c != EOF) //WHILE NOT END OF FILE OR NEW LINE (USER PRESSED ENTER)
              {
                   pathStr[i++] = (char)c;

                   if(i == current_size)
                   {
                        current_size = i+max_size;
                        pathStr = realloc(pathStr, current_size);
                   }    
              }
  }
}

Answer 1

You aren't closing all the files ;-)

FILE *fp = fopen(strIn, "r");
if(fopen(strIn, "r") == NULL) //for inputting file

Same applies to your output.

I think you meant something more like:

FILE *fp = fopen(strIn, "r");
if(fp == NULL) //for inputting file
{
     // error handling.

Answer 2

No, no! You're opening every file twice (and only closing once)!

  /* Bad! */
  dir = opendir(pathStr); //allcate it a path
  if(opendir(pathStr) == NULL)
  { printf("Error: %d (%s)\n", errno, strerror(errno));}
  int k;

  /* Correct */
  dir = opendir(pathStr); //allocate it a path
  if(!dir) { 
    printf("Error: %d (%s)\n", errno, strerror(errno));
    return;
  }

You're also doing the same thing with fopen(). In both places :)

Just check the pointer ; don't call "fopen()" a second time; don't call "opendir()" a second time!

Also: please don't put code on the same line as your opening brace. OK?

Answer 3

dir = opendir(pathStr); //allcate it a path
if(opendir(pathStr) == NULL)

(...)

FILE *fp2 = fopen(dirOut, "w"); //for outputting file
if(fopen(dirOut, "w") == NULL)

(...)

FILE *fp = fopen(strIn, "r");
if(fopen(strIn, "r") == NULL) //for inputting file

Here you open the file twice but only store the pointer once. Change these to:

FILE *fp = fopen(strIn, "r");
if(fp == NULL) //for inputting file

and the other one in the same way.