[beginner] get file address from file pointer

hi,

can anyone tell me how to get the full file address from a file pointer?

I use the dev-c++ compiler and when I ask the user to enter the filename to save the data to
and the user just enter a name like "text.dat" without c:\ (so not the full address). it's saved to my dev-c++ folder on the computer where the compiler is installed.

But when I run the executable file on another computer and the user give the input "text.dat" the text.dat file is found in the same directory as where the executable is in, can you explain that to?

thank you,

Use getcwd() to find out which directory the program considers to be the current directory.

When you look for a file with a plain name, the system usually tries to look for it in the following places (and not necessarily in this order):

• In the current directory that it is in.
• In O/S system directories (ie. "C:\Windows")
• In every directory listed inside the Environment variable PATH
• Possibly a number of other places.

okay,

I have another question :)
I have this

char *filename = read_dyn_string();
fptr = fopen(filename,"wb");

let say the user can enter: "1234.dat" , "c:\1234.dat" when asking by the function read_dyn_string() (that just read a string and trim the newline at the end and put the string in the heap)

and let say fopen succesfully open the file and fwrite succesfully write the data to the file, before closing the file I want to print this to the stdout printf("Data saved to %s", fulladdress);

so how do I get the fulladdress? when the user might enter just the file name or enter the full file address?

thank you,

I've already told you - getcwd().

If they type in something beginning with D:\ then it's an absolute path, and that is where the file will be.

If not, then you basically take the result of getcwd() and strcat() the name they typed in.

By printing the current working directory just before the filename:

Code:

---

char buffer[BUFSIZ];
   
getcwd(buffer, sizeof(buffer));
printf("%s", buffer);

---

Quote:

---

Originally Posted by Salem

I've already told you - getcwd().

If they type in something beginning with D:\ then it's an absolute path, and that is where the file will be.

If not, then you basically take the result of getcwd() and strcat() the name they typed in.

---

sorry,

cause I couldn't find the reference for the function (at http://www.cppreference.com/ and http://www.acm.uiuc.edu/webmonkeys/book/c_guide/ )

could you give me a better reference site links ?

...

and the method that you explain to me, does that means that I have to examine the beginning of the string to check if there is c:\ d:\ e:\ f:\ ? or maybe I could just check for ":\" ?

KONI gave you the ref example on how to use it. At these time google should be your best example.

here you go getcwd()

ssharish2005

http://man.he.net/man3/getcwd

Quote:

---

and the method that you explain to me, does that means that I have to examine the beginning of the string to check if there is c:\ d:\ e:\ f:\ ? or maybe I could just check for ":\" ?

---

if the user enters the absolute path then you will have check for the drive which the user has entered.

Or if the user donst enter and absolute path and just entered the file name, use getcwd function to get the current working directory and append the file name to that path and then open the file.

ssharish2005

the user can enter a string like this: :abcd
(with the ":")

where could the file be saved? cause it's saved succesfully and I can open it with the same program, but I can't find it anywhere on my drive

":abcd" is an invalid file name (at least for Windows XP). Your program must change the name somehow. Print the name of the file that it opened:

Code:

---

char filename[/*...*/];
puts(filename);
fopen(filename, "");

---

well, this is what I have

Code:

---

int saveListNewName(char *filename)
{
    FILE *fptr;
    int i;
    char *fileAddress;

    //fprintf(stdout,"Saving records to %s\n", filename);
    printf("file name is >> %s\n",filename);
    fptr = fopen(filename,"wb");
    ....
}

---

the filename string is ":abcd"
and this is the the output from the printf -> file name is >> :abcd
and fopen succeed in opening the file (creating it)

this is the rest of my function

Code:

---

 
  ....
  if (fptr == NULL)
    {
        fprintf(stderr, "Could not save to %s - %s\n",
                        filename, sys_errlist[errno]);
        return 0;

    }
    for (i = 0; i < count; i++)
    {
        if (fwrite(cdPointers[i], sizeof(cd_t), 1, fptr) < 1)
        {
            fprintf(stderr, "Could not write to %s - %s\n",
                                filename, sys_errlist[errno]);
            return 0;
        }
    }
    puts("File have been saved");
    fileAddress = getDir(filename);
    printf("File have been saved to %s",fileAddress);
    free(fileAddress);
    fclose(fptr);
    return 1;

}

---

[/code]

That's odd. You're using Dev-C++, eh?

Try a simple program like this.

Code:

---

#include <stdio.h>

int main(void) {
    const char *filename = ":file";
    FILE *fp = fopen(filename, "w");

    perror(filename);

    if(fp) fclose(fp);
}

---

If you get output like

Code:

---

:file: No error

---

then your system can write to that file. If you get an error, then there's something up with your code above.

If you do create that file and you simply can't find it anywhere, I recommend setting the date to say a year in the future, running your program, and searching your entire hard drive for files modified in the past day. Of course, that should be a last resort as it would take a long time.

Some locations to check:

Code:

---

.  // the directory the program executable is in
C:\Windows
C:\Windows\Temp
C:\Dev-Cpp
C:\Dev-Cpp\Bin
C:\Documents and Settings
C:\Documents and Settings\User
C:\Documents and Settings\User\My Documents
C:\Documents and Settings\User\temp

---

etc.

[edit] Opening the file in binary mode may have something to do with it. Try it and see. [/edit]

I do get the output => :file: No error

I have try to search (with indexing service disable) the entire c partition, but nothing found, I will try yours tips of setting the date a year further