CODEWITHSUNDEEP
cio
Clueless Programmer
Clueless Programmer

Reputation: 61

Read will loop end of file

I'm writing a C code that will read content of file and output it on the terminal. This is my code so far:

rdfd = open(address, O_RDONLY);
read(rdfd, reader, 1);
while(rdfd != 0){ //will end if EOF is reached
    for(x=0; x<1; x++) printf("%c", reader[x]); //for printing at the terminal
    read(rdfd,reader,1);
}

Now, for an example, I have an index.html file with the ff content:

<html>
    <body><h1>HELLO WORLD</h1></body>
</html>

The program will print something like this:

<html>
    <body><h1>HELLO WORLD</h1></body>
</html>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> (...)

The > will just go on infinitely. I don't know why. Was there something wrong with the while condition?

Upvotes: 1

Views: 54

Answers (1)

fileoffset
fileoffset

Reputation: 976

rdfd is the File Descriptor of the file you are reading from. Testing it for zero (while(rdfd != 0) actually doesn't do anything useful. If you want to test whether the file was opened correctly (you should) test if for < 0.

If you want to know when the end of the file is reached, check the return value from the read call, i.e:

int bytesRead = read(rdfd, reader, 1);

while (bytesRead > 0)
{ ... 
  bytesRead = read(rdfd,reader,1);
}

Upvotes: 1

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