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C stdio fread() Function

❮ C stdio Library


Example

Read some data from a file:

FILE *fptr;

fptr = fopen("filename.txt", "r");

char data[20];
int n = fread(data, 1, 19, fptr);

// printf() and other string functions need to find a null terminating character
data[n] = '\0';

printf("%s", data);

fclose(fptr);

Definition and Usage

The fread() function reads data from a file and writes into a block of memory.

The fread() function is defined in the <stdio.h> header file.


Syntax

fread(void * destination, size_t size, size_t amount, FILE * fptr);

The size_t data type is a non-negative integer.

Parameter Values

Parameter Description
destination Required. A pointer to a block of memory where the data will be written.
size Required. The size of an element in the block of memory.
amount Required. The number of elements to read from the file and write into the block of memory.
fptr Required. A file pointer, usually created by the fopen() function.

Technical Details

Returns: A size_t value representing the number of elements that were read. If this number is different than the amount parameter then the end of the file has been reached or an error occurred.

❮ C stdio Library

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