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cbinaryfilesfread

How can you binary read blocks of data till EOF in C?

I try to learn to binary read blocks of data, instead to read the values one by one. I succesfully read the blocks which contains N bytes of data, but if the last block is not N bytes, the data is lost, because of the while condition.

#include<stdio.h>
#include<stdlib.h>

int main(){
int buffer[512];
FILE *data = fopen("new_file.bin","rb");
while( fread(&buffer,sizeof(int),512,data) )
{
... do something
}
return 0;
}

If the next block is for example 400 bytes, then the data from that block won't be used. Any idea how can I read all the data till EOF ?

Solution

  • Instead of reading N-byte blocks, you should read N 1-byte blocks.

    #include<stdio.h>
#include<stdlib.h>

#define N 2048

int main(){
    char buffer[N];
    FILE *data = fopen("new_file.bin","rb");
    size_t size_read;
    while( (size_read = fread(buffer,1,N,data)) > 0 )
    {
        ... do something
    }
    return 0;
}