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Function Details : fread

size_tfread(void * ptr,size_t size,size_t nmemb,FILE * stream) ;

Return Type : size_t

Platform-specific unsigned type for array indices and memory sizes.
Read about return values of fread function .

1st Parameter Type : void *

New Generic pointer that can point to any data type

1st Parameter

Pointer to the buffer where the data read from the file will be stored

2nd Parameter Type : size_t

Platform-specific unsigned type for array indices and memory sizes.

2nd Parameter

The size of each element to be read, in bytes

3rd Parameter Type : size_t

Platform-specific unsigned type for array indices and memory sizes.

3rd Parameter

The number of elements to read

4th Parameter Type : FILE *

Pointer to FILE structure for file operations

4th Parameter

Pointer to the file stream from which data is to be read

Read more about parameters of fread in parameters section
The freadfunction in C language Reads data from the given stream into the array pointed to by ptr.
The fread function reads nmemb elements of data, each size bytes long, from the stream pointed to by stream, storing them at the location given by ptr. The file position indicator for the stream is advanced by the number of bytes successfully read. This function is commonly used for reading binary data or large chunks of data from files.

To Summarize the Workflow:
  1. 1.
    Function reads blocks of data from a file stream into memory
  2. 2.
    Takes four parameters: destination buffer, size of each element, number of elements, stream
  3. 3.
    Returns number of complete elements successfully read
  4. 4.
    Returns 0 on EOF before any read or on error
  5. 5.
    May return less than count if partial read occurs
  6. 6.
    Works with ferror() and feof() to determine exact cause of failure


Success

Failure

Yes

No

fread(void *ptr, size_t size, size_t count, FILE *stream)

Read operation

Return count (all elements read)

Partial read?

Return number of elements read

Return 0 Check feof/ferror




Read more about return type and value offread function in return section.
The freadfunction takes 4 parameters:
  • •
    void * `ptr`: Pointer to the buffer where the data read from the file will be stored
  • •
    size_t `size`: The size of each element to be read, in bytes
  • •
    size_t `nmemb`: The number of elements to read
  • •
    FILE * `stream`: Pointer to the file stream from which data is to be read
The fread function return value :
  • Returns the number of elements successfully read (which may be less than nmemb if a read error or end-of-file is encountered)
  • If size or nmemb is zero, fread returns zero and the contents pointed to by ptr and the state of the stream remain unchanged

Output

This example demonstrates basic usage of `fread` to read content from a text file. It reads up to 99 bytes from the file into a buffer and then prints the content.