Does fread move the file pointer?

c, file, fread

Solution

Answer: Yes, the position of the file pointer is updated automatically after the read operation, so that successive `fread()` functions read successive file records.

Clarification: `fread()` is a block oriented function. The standard prototype is:

size_t fread(void *ptr,
             size_t size,
             size_t limit,
             FILE *stream);

The function reads from the stream pointed to by `stream` and places the bytes read into the array pointed to by `ptr`, It will stop reading when any of the following conditions are true:

- It has read `limit` elements of size `size`, or

- It reaches the end of file, or

- A read error occurs.

`fread()` gives you as much control as `fgetc()`, and has the advantage of being able to read more than one character in a single I/O operation. In fact, memory permitting, you can read the entire file into an array and do all of your processing in memory. This has significant performance advantages.

`fread()` is often used to read fixed-length data records directly into structs, but you can use it to read any file. It's my personal choice for reading most disk files.

Problem

Original source