function pointer not pointing

[darfader]

Hi,

am I right in thinking that calling p_fp[IN_FILE] will always go to the _start_ of the file ?

in the snippet below, I am getting a count from LAST_FILE but not from IN_FILE, I have swapped them round just in case and when I do I get 5 0 instead of 0 5 and I should be getting 9 5 or 5 9

I think I have included everything that is relevant,

#define OPEN_FILE_COUNT  6
#define IN_FILE          0
#define OUT_FILE         1
#define LOG_FILE         2
#define YEAR_FILE        3
#define HIST_FILE        4
#define LAST_FILE        5


FILE * p_fp[OPEN_FILE_COUNT];


void file_open(char * inp_file, char * last_month, FILE ** fp)
{
   if(!(fp[IN_FILE] = fopen(inp_file, "r")))
      error_func("In file_open().", "Error : fopen(INPUT_FILE)", SYS | FATAL);
   ... /* same for all files */


void check_activity(FILE ** p_fp)
{
int countA = 0, countB = 0;
char ch;

   while((ch = fgetc(p_fp[IN_FILE])) != EOF)
      if(ch == '\n')
         countA++;

   while((ch = fgetc(p_fp[LAST_FILE])) != EOF)
      if(ch == '\n')
         countB++;

   printf("this month, last month %d %d\n", countA, CountB);
   ...

tia,

[twm]

>FILE * p_fp[OPEN_FILE_COUNT];
Is this global? If so why do you bother having the fp and p_fp parameters to those two functions?

>/* same for all files */
All six? I only see two parameters that could be used as file paths to open.

>

while((ch = fgetc(p_fp[IN_FILE])) != EOF)
   if(ch == '\n')
      countA++;

while((ch = fgetc(p_fp[LAST_FILE])) != EOF)
   if(ch == '\n')
      countB++;

Why not:

/* Line Count */
unsigned long lc(FILE *fd) {
  unsigned long rc;
  int c;

  rewind(fd);
  rc = 0;
  while ((c = getc(fd)) != EOF) {
    if (c == '\n')
      rc++;
  }

  return rc;
}

...

countA = lc(p_fp[IN_FILE]);
countB = lc(p_fp[LAST_FILE]);

>am I right in thinking that calling p_fp[IN_FILE] will always go to the _start_ of the file ?
As long as you've just opened it and done nothing with the loc pointer, or rewound the loc pointer, or done an fseek or fsetpos to the beginning.

[Dave_Sinkula]

As I mentioned previously, fgetc returns an int.

char ch;
while((ch = fgetc(p_fp[IN_FILE])) != EOF)

Do you still have this problem after changing ch to an int?

Also, you have a "global" p_fp and a parameter p_fp for the function check_activity. Do you know which one hides the other?

[EDIT]
"function pointer not pointing"
A function pointer is not the same as a FILE pointer.
[/EDIT]

[darfader]

twm:
Dave_Sinkula:

Hi,

I was trying not to post the whole code, because it is probably larger than I can fit in one post, either by the rules of the post, the amount of chars or just spamming

No, FILE ** is not global, it is restricted to int main(), hence the reason for it being passed round the functions, and yes ch is already an int after your last advice.

IN_FILE and LAST_FILE and all the others have already been opened, and used by other functions before we get here, but as I am not specifically resetting LAST_FILE, I wondered why I could count one and not the other ?


thanks for your help, as usual