Hello everybody
i need to read a text file line by line in unix system programming. i know that to read a file we need to use the read (fd, buf, BUF_SIZE) function but how to read this file line by line. do i need to use the getline() function?
thank you

The low level read() function is not a standard C library function. It has been there "forever," and, in fact I thank that the low level functions (open(), read(), write(), etc.) are used to implement the standard functions fopen, fgets, printf, etc., but it is not an official part of the standard C library, and, therefore, applications that use this may not be very portable.

I think that most programmers stick with standard functions: Open with fopen(), read lines with fgets(). Stuff like that.

Here's a program to read all lines of a file and print them out with line numbers. A summary of the number of lines is printed:

This works with compilers for Windows platforms, Linux platforms, and anything else that has I/O that complies with the standard language and library implementation.

Regards,

Dave

Footnote: The getline() function is not in the C standard library. If your system has low-level I/O functions (open(), read(), etc.), you can certainly write a getline() function that uses low-level read() operations. You can also write any other convenient functions (scanf(), printf(), etc.) using low-level read() and write(), but the work has already been done with the standard library buffered I/O functions.

Thank oyu Dave your reply was very helpful

can someone please explain to me the while (fgets (line_buffer line and how it read the file.. whats sizeof??

Daniel

When you looked up the functions, what was it you didn't understand?

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