C stdio fread() Function
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. |
|---|