error catcher in all fds

.gitignore

@@ -0,0 +1,2 @@
+hello
+gpio

main.c

@@ -6,26 +6,46 @@ int main(int argc, char *argv[]){
 	int fd;
 	//export
 	fd= open("/sys/class/gpio/chip0/export",O_WRONLY);
+	if (fd<0){
+		perror("Error opening the GPIO path");
+		return -1;
+	}
 	write(fd,"17",2);
 	close(fd);
 	//pin direction
 	fd= open("/sys/class/gpio/chip0/gpio17/direction",O_WRONLY);
+	if (fd<0){
+		perror("Error opening the GPIO path");
+		return -1;
+	}
 	write(fd,"out",3);
 	close(fd);
 	
 	//pin value
 	fd= open("/sys/class/gpio/chip0/gpio17/value",O_WRONLY);
+	if (fd<0){
+		perror("Error opening the GPIO path");
+		return -1;
+	}
 	write(fd,"1",1);
 	close(fd);
 	sleep(1);
 	//pin value
 	fd= open("/sys/class/gpio/chip0/gpio17/value",O_WRONLY);
+	if (fd<0){
+		perror("Error opening the GPIO path");
+		return -1;
+	}
 	write(fd,"0",1);
 	close(fd);
 	sleep(1);
 
 	//unexport
 	fd= open("/sys/class/gpio/chip0/unexport",O_WRONLY);
+	if (fd<0){
+		perror("Error opening the GPIO path");
+		return -1;
+	}
 	write(fd,"17",2);
 	close(fd);