Reading file contents

#include <stdio.h>
#include <fcntl.h>
#include <sys/types.h>
#include <unistd.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
 
#define BUFFER_SIZE 16
 
/**
 * @brief main The program entry point
 * @param argc The number of arguments
 * @param argv The command line arguments
 * @return Returns exit code
 */
int main(int argc, char* argv[]){
 
    // if not enough parameters supplied
    if(argc < 2){
        printf("File name was not given by arguments\n");
        exit(1);
    }
 
    // we expect the input file name to be provided as the 1st command-line argument 
    const char* filename = argv[1];
 
    // open file in read-only mode, expecting that file already exists
    int file = open(filename, O_RDONLY);
 
    // something went wrong (file does not exist, user does not have read access to the file, etc.)
    // function strerror(errno) gets the standard error corresponding to the given error code 
    if(file == -1){
        printf("Something went wrong while opening the file. Error %s\n", strerror(errno));
        exit(errno);
    }
 
    // allocate a buffer of a given size + 1 byte for appending termination character \0
    char* buffer = malloc(BUFFER_SIZE + 1);
 
    // the variable will be used to count number of bytes we could read from the file overall
    long overallBytes = 0;
 
    // the variable will be used to capture number of read bytes in every read iteration
    long readBytes = 0;
 
    // repeat until we want to stop
    while(1 == 1){
 
        // try reading the next BUFFER_SIZE bytes from the file into a buffer
        readBytes = read(file, buffer, BUFFER_SIZE);
 
        // we may get some errors while reading the file for various reasons, so the case needs to be handled
        if(readBytes == -1){
            printf("Something went wrong while reading the file. Error %s\n", strerror(errno));
            exit(errno);
        }
 
        // if we receive 0 bytes from the read operation, then there is no more data to read
        if(readBytes == 0){
            break;
        }
 
        // increase number of overall bytes
        overallBytes += readBytes;
 
        // (only for printing purposes) 
        // to print the read data to the console, we need to terminate the next read chunk with \0 symbol  
        buffer[readBytes] = '\0';
 
        // print the next chunk of read data
        printf("%s", buffer);
    }
 
    // close the file as we don't need it anymore
    close(file);
 
    // release allocated memory
    free(buffer);
 
    // report success
    printf("Completed reading file. Overall bytes: %ld\n", overallBytes);
 
    return 0;
}

gcc read.c -o read