Cannot open file with fopen(); function - C Programing

Question

1. I am trying to create a program that using the fopen(); function.

2. My problem is that fopen(); cannot find the file.

   • when i am using perror("Error"); the output is Error: No such file or directory.

3. I have read this articles and they did`not solved my problem:

   • fopen() returning a NULL pointer, but the file definitely exists
   • Unable to open a file with fopen()
   • It means i have tried to use fopen(); with the exec path to the file, and i have checked that the filename is the specific filename that i am looking for.
   • I have also used exec("pwd"); to see that i am the correct directory.

4. My OS is ubuntu mate 20.04.

5. Here is my Code:

   /* File Name: firstTransaction.c 
    * File Mission: scan the input files and make the first transaction.
    */
   
   #include "defines.h"
   
   /*
    * first transaction file:
    * Allocating new memory for the assembly source file.
    * Scanning the assembly source file.
    * @param filename - the filename of the file that needs to be converted by the program.
    * @return output and files -
    *      output the assembly source file in a machine code.
    *      return extern, entry and object files.
    */
   
   /* function prototype */
   
   extern char * readText(FILE * ptr, long ic, long dc); /* the function defined on assistanceFunctions.c file */
   
   int firstTransaction(int * cf, char **av)
   {
       FILE * fp; /* a pointer for fopen function */
       char * filteredFile = NULL;
       long ic = 100, dc = 0; /* declaration and initialization of the instruction counter and current data counter */
       int i = 0, j = 0; /* indexes */
       int cfh = 0; /* compatible file holder */
       int fileNameLength = (int)strlen(av[i]); /* computing the first filename length to allocate memory */
       char * fileName = (char*) calloc(fileNameLength,sizeof (char)); /* allocating memory for the first filename */
       system("pwd");
       while(cf[i] != 0) /* while there is more compatible files to open */
       {
       cfh = cf[i]; /* cfh - compatible file holder, cf - compatible file array, set the next compatible file to cfh */
       strcpy(fileName,av[cfh]); /* copy the file name from the argv array */
       fp = fopen("fileName","r"); /* open the first compatible file for read */
       if(fp == NULL) /* if file does not exists */
       {
           perror("Error"); /* print the error - why the file not opened */
           i++; /* increment i by one and try to open the next filename */
       }else /* if the file was opened successfully, start scanning the file */
       {
           /*filteredFile = */ readText(fp, ic, dc); /* calling readText function with pointer to the start of the file that was opend by fopen function */
          /* while(filteredFile[j] != EOF)
               {
                   putchar(filteredFile[j]);
                   j++;
               }
           /* DONT FORGET TO CLOSE WITH FCLOSE(); */
       }
       }
       return 0;
   }
   
   
   

Here is some screenshots with the tested solutions that failed from the other articles:

Edited after NeonFire answers:

1. My first code used fp = fopen(fileName,"r"); but my error message was made manually this way: printf("error, %s file does not exists\n", fileName); /* print error message to the user */
   • this cause that i did`not find my real error.
   • then i changed to fp = fopen("fileName","r"); and used perror("Error"); instead of the first and right way.
   • after i read NeonFire answers i got a new error Error: Too many open files.
   • i removed the backups file from the directory and i still have the same error.

Edited after Ted Lyngmo comment: i did had to close the file to solve the - "to many file to open error".

Answer 1

your fp = fopen("fileName","r"); is incorrect. Remove the quotes from fileName so it refers to your variable char * fileName , not a string "fileName" :)