Continuously save images taken with an OV5642 connected to a Pi 4B to a text file

Save_To_Pi.c

#include <stdlib.h>
#include <stdio.h>
#include <stdbool.h>
#include "ArduCAM.h"
#include "sccb_bus.h"
#include <unistd.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <pthread.h>
#include <signal.h>
#include <netdb.h>

unsigned char is_first_time_printing_to_file = 1;
void print_image_data();

unsigned int length_cam1;

int main(int argc, char *argv[])
{
    pioInit();
    ArduCAM_CS_init( CAM_CS1, -1, -1, -1 );   // init the cs

    sccb_bus_init();
    spiInit(4000000, 0); //8MHZ
    Arducam_bus_detect( CAM_CS1, -1, -1, -1 );

    resetFirmware( CAM_CS1, -1, -1, -1 );  //reset the firmware
    ArduCAM_Init(sensor_model);
    // OV5642_640x480, OV5642_1024x768, OV5642_1280x960, OV5642_1600x1200, OV5642_2048x1536, OV5642_2592x1944
    unsigned char jpeg_size = OV5642_640x480;
    OV5642_set_JPEG_size(jpeg_size);
    while (1) {
        singleCapture(CAM_CS1);
        print_image_data();
        sleep(1);
    }
    return 0;
}

void print_image_data() {
    printf("Writing image data to file.\n");
    // open modes: https://www.ibm.com/docs/en/zos/2.4.0?topic=functions-fopen-open-file
    FILE *f = NULL;
    char filename[] = "image.txt";
    if (is_first_time_printing_to_file == 1) {
        f = fopen(filename, "wb");
        is_first_time_printing_to_file = 0;
    } else {
        f = fopen(filename, "ab");
    }
    size_t written = fwrite(readbuf, sizeof(unsigned char), length * sizeof(unsigned char), f);
    if (written == 0) {
        printf("Error during writing to file !\n");
    } else {
        printf("Successful write!\n");
    }
    fclose(f);
}

I didn't comment the full list of resolutions at line 31 but they're easy to find lol