How to install gcc

Kit Bishop

@Boken-Lin Thanks - I'll give it a try.
Since I already use my USB device for /overlay, presumably I will need to re-partition my USB drive with two partitions:

An ext4 partition for /overlay
A swap partition for swap

Any suggestions as to what would be a suitable size for the swap partition?

Also, once all details are ironed out, perhaps the details should be made the subject of a Wiki tutorial (with reference too to the usage of the USB drive for overlay and swap)

Boken Lin

@Kit-Bishop You can try a swap of 512MB, it should be enough for compilation purposes.

And yup, I will write up a separate tutorial for that.

Kit Bishop

@Boken-Lin I have had a try at setting up swap on a USB drive partition and believe it is actually working. My Omega still works fine after the steps I describe below and as shown below I believe I have the expected swap space. Note in the steps I describe below I wanted to maintain a partition on the USB drive for overlay.

Steps I have performed and some associated information are:

Partitioned my USB drive with 2 partitions as follows:
- Partition 1: 100MByte partitioned as linuxswap
- Partition 2: Rest of drive as ext4 partition for overlay
Performed the steps necessary to use partition 2 for /overlay directory
Resultant /etc/config/fstab is:
config 'global'
option anon_swap '0'
option anon_mount '0'
option auto_swap '1'
option auto_mount '1'
option delay_root '5'
option check_fs '0'

config 'swap'
option device 'sda1'
option uuid 'b1b4771d-fc9c-4cc9-811d-04f4f8a8925d'
option enabled '1'

config 'mount'
option target '/overlay'
option uuid 'b2580ec6-6d9f-4514-930a-df481be20b99'
option enabled '1'
4. Output from the free command before setting up the swap was:
total used free shared buffers
Mem: 61180 27184 33996 92 3484
-/+ buffers: 23700 37480
Swap: 0 0 0
5. Output from the free command after setting up the swap is:
total used free shared buffers
Mem: 61180 28092 33088 92 3644
-/+ buffers: 24448 36732
Swap: 1028124 0 1028124
This seems to indicate that swap is operative

Johan Simons

@Boken-Lin
I am using CentOS 6.5
Getting a specific toolchain would be great
thx

Johan Simons

@Boken-Lin
Hi there, is there any progress on the issue of a toolchain for 32bit CentOS 6.5 ???
thx

Boken Lin

Hi @Johan-Simons, please download the SDK Here: https://s3-us-west-2.amazonaws.com/onion-downloads/openwrt/OpenWrt-SDK-ar71xx-generic_gcc-4.8-linaro_uClibc-0.9.33.2.Linux-i686.tar.bz2.
The Toolchain is here: https://s3-us-west-2.amazonaws.com/onion-downloads/openwrt/OpenWrt-Toolchain-ar71xx-generic_gcc-4.8-linaro_uClibc-0.9.33.2.Linux-i686.tar.bz2

Cheers!

Johan Simons

@Boken-Lin said:

Hi @Johan-Simons, please download the SDK Here: https://s3-us-west-2.amazonaws.com/onion-downloads/openwrt/OpenWrt-SDK-ar71xx-generic_gcc-4.8-linaro_uClibc-0.9.33.2.Linux-i686.tar.bz2.
The Toolchain is here: https://s3-us-west-2.amazonaws.com/onion-downloads/openwrt/OpenWrt-Toolchain-ar71xx-generic_gcc-4.8-linaro_uClibc-0.9.33.2.Linux-i686.tar.bz2

Cheers!

It is working, thx for the solution

Boken Lin

@Johan-Simons Awesome!

Justin Sowers

@Kit-Bishop @Boken-Lin Could you write-up a quick guide to setting-up a swap partition? I think the bones are in this thread, but not the full guide. I have compiled make, m4, and autoconf from source on the Omega, and have successfully installed them, as well as a few other pieces of software. However, building and running bigger tools like SWIG, likely needs swap. I intend to use SWIG to generate a Ruby extension for the C++ new-gpio lib. BtW, other than running a little slow, the Omega is a fine build machine.

Kit Bishop

@Justin-Sowers I will write a quick guide for this and post it here in a .pdf file - keep watching.
@Boken-Lin When I have done the guide, would it be a suitable candidate for a Wiki Tutorial?

Kit Bishop

@Justin-Sowers @Boken-Lin I have created a new post (https://community.onion.io/topic/533/using-linux-swap-space-on-the-omega) that contains the guide.
Hope it is useful.

Ahmed Mkadem

@Kit-Bishop then how can you compile a C program ? can you explain it to me please ?

Kit Bishop

@Ahmed-Mkadem I compile C/C++ using cross compilation on a Linux system (I use Kubuntu).
Some details can be found at https://community.onion.io/topic/9/how-to-install-gcc/22

You may also be interested in the set of C++ libraries and programs I have produced for perfroming GPIO, I2C and Arduino access on the Omega. The full set of these can be found at https://github.com/KitBishop/Omega-GPIO-I2C-Arduino The various documentation .pdf files therein give more details.

You might in particular look at the template program that is included in the above referenced package - see https://github.com/KitBishop/Omega-GPIO-I2C-Arduino/tree/master/iotemplate and its documentation at https://github.com/KitBishop/Omega-GPIO-I2C-Arduino/blob/master/iotemplate/iotemplate.pdf

Hope that helps

Ahmed Mkadem

@Kit-Bishop Thank you !! this is helpful

anglo marc

@Kit-Bishop hi dear
im new with Linux and want to use the cross compiler
can you please explain ho to do these steps !
setting the environment variables , install the tool chain ?
also the omega didn't have sftp server so how can i transfer the executable file ?

anglo marc

@Boken-Lin said in How to install gcc:

@Justin-Sowers The Omega (or most OpenWRT devices for that matter) has very limited computational resources, so people don't generally compile anything directly on them, which is probably why you are unable to find packages that allow you to install build tools. However, things like make and autoconf are just binaries that can you compiled from source. So if you want to compile it for the Omega, it's simply a matter of creating a Makefile in your cross-compile environment and build an opkg package out of them.

hi dear
is there ant tutorial explain that process in actual details ?

José Luis Cánovas

@anglo-marc you can start from here.

Przemyslaw Downar

hello i install gcc. I downloaded library i2c from https://github.com/OnionIoT/i2c-exp-driver

onion-i2c.c
onion-i2c.h
onion-debug.c
onion-debug.h

wrote a program, copy files to usr/c/ and run gcc

gcc  -I usr/c/ -o program usr/c/HTU21D.c

but while compiling gets an error:

/tmp/ccnKdEjA.o: In function `getTemperature()':
HTU21D.c:(.text+0x88): undefined reference to `i2c_writeBytes'
HTU21D.c:(.text+0x94): undefined reference to `i2c_writeBytes'
collect2: error: ld returned 1 exit status

my program:

#include "HTU21D.h"
int main ()
{
    printf("Hello world!\n ");
    //printf("%5.2fC\n", getTemperature());
    return 0;
}
double getTemperature()
{
unsigned char buf [32];
int     status;
 i2c_writeBytes(0, 0x80, 0xF3, 0, 0);
//status = i2c_read(0, HTU21D_I2C_ADDR, HTU21D_TEMP, buf, 3);

unsigned int temp = (buf [0] << 8 | buf [1]) & 0xFFFC;

double tSensorTemp = temp / 65536.0;
return -46.85 + (175.72 * tSensorTemp);
}

file .h

#ifndef _HTU21D_H_
#define _HTU21D_H_

#include <stdlib.h>
#include <stdio.h>
#include <math.h>
#include <unistd.h>
#include <onion-i2c.h>
#define   HTU21D_I2C_ADDR 0x80

#define   HTU21D_TEMP     0xF3
#define   HTU21D_HUMID    0xF5
double getTemperature();
#endif

José Luis Cánovas

@Przemyslaw-Downar

Your file.h should be named HTU21D.h.
Delete the space after the -I argument.
Move every unnecessary #include from the .h to the c/ cpp file. In this case, all.

Chris Stratton

None of those suggestions are likely to help. Unless there are missing macro definitions, an "undefined reference" error is an issue with linking rather than compilation.

You need to be passing whatever implements this function to the linker, either as a library or as an additional object file, or by providing it to the compiler as an additional source file to be built.