codezero/tasks/test0/src/fileio.c

#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <string.h>
#include <tests.h>

int fileio(void)
{
	int fd;
	ssize_t cnt;
	int err;
	char buf[128];
	off_t offset;

	char *str = "I WROTE TO THIS FILE\n";

	if ((fd = open("/home/bahadir/newfile.txt", O_RDWR | O_CREAT | O_TRUNC, S_IRWXU)) < 0) {
		perror("OPEN");
		return -1;
	}
	printf("Created newfile.txt\n");

	if ((int)(cnt = write(fd, str, strlen(str))) < 0) {
		perror("WRITE");
		return -1;
	}

	if ((int)(offset = lseek(fd, 0, SEEK_SET)) < 0) {
		perror("LSEEK");
		return -1;
	}
	if ((int)(cnt = read(fd, buf, strlen(str))) < 0) {
		perror("WRITE");
		return -1;
	}

	printf("Read: %d bytes from file.\n", cnt);
	if (cnt) {
		printf("Read string: %s\n", buf);
	}

	if ((err = close(fd)) < 0) {
		perror("CLOSE");
		return -1;
	}

	return 0;
}

#if defined(HOST_TESTS)
int main(void)
{
	printf("File IO test:\n");
	if (fileio() == 0)
		printf("-- PASSED --\n");

	return 0;
}
#endif