Difference between revisions of "Category:How to - Build helloworld"

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(Created page with '==Overview== What follows is a description for building C programs on a workstation using the cross-build tools of OpenEmbedded directly but not using the bitbake/recipe framewo…')
 
m (More detail about TMPDIR)
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==Overview==
 
==Overview==
  
What follows is a description for building C programs on a workstation using the cross-build tools of OpenEmbedded directly but not using the bitbake/recipe framework.
+
What follows is a description for building C programs on a workstation using the cross-build tools of [http://wiki.openembedded.net/index.php/Main_Page OpenEmbedded], but not using the bitbake/recipe framework.
 
+
  
 
==Setup==
 
==Setup==
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Follow the instructions for [http://www.gumstix.net/Setup-and-Programming/view/Overo-Setup-and-Programming/Setting-up-a-build-environment/111.html setting up a build environment] to get the cross-build tools correctly installed.
 
Follow the instructions for [http://www.gumstix.net/Setup-and-Programming/view/Overo-Setup-and-Programming/Setting-up-a-build-environment/111.html setting up a build environment] to get the cross-build tools correctly installed.
  
 +
While you don't necessarily need to build a complete image to get the cross-tools for a C program, as a practical matter, successfully building an image is a good test that the cross-tools are correctly installed.
 +
 +
The tools are built under the TMPDIR directory declared in ${OVEROTOP}/build/conf/site.conf.
 +
 +
TMPDIR defaults to ${OVEROTOP}/tmp, but you can point it somewhere else.
 +
 +
For instance, putting TMPDIR on a faster disk can speed your build.
  
 
==Makefile==
 
==Makefile==
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  # OVEROTOP is normally ${HOME}/overo-oe  
 
  # OVEROTOP is normally ${HOME}/overo-oe  
 
  #
 
  #
  # OETMP is the same as TMPDIR as defined in ${OVEROTOP}/build/conf/site.conf
+
  # OETMP is the same as TMPDIR as defined in ${OVEROTOP}/build/conf/site.conf
 
  #
 
  #
 
   
 
   
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  clean:
 
  clean:
 
         rm -f ${TARGET} ${OBJS} *~
 
         rm -f ${TARGET} ${OBJS} *~
 
  
 
==Distribute==
 
==Distribute==
  
Then copy the resulting target executable to the overo.
+
Copy the resulting target executable to the overo.
  
 
1. If you are using [http://www.gumstix.net/Setup-and-Programming/view/Overo-Setup-and-Programming/Creating-a-bootable-microSD-card/111.html a microSD card], copy your executable to the rootfs before you unmount it in the final step.
 
1. If you are using [http://www.gumstix.net/Setup-and-Programming/view/Overo-Setup-and-Programming/Creating-a-bootable-microSD-card/111.html a microSD card], copy your executable to the rootfs before you unmount it in the final step.

Revision as of 07:08, 1 January 2010

Overview

What follows is a description for building C programs on a workstation using the cross-build tools of OpenEmbedded, but not using the bitbake/recipe framework.

Setup

Follow the instructions for setting up a build environment to get the cross-build tools correctly installed.

While you don't necessarily need to build a complete image to get the cross-tools for a C program, as a practical matter, successfully building an image is a good test that the cross-tools are correctly installed.

The tools are built under the TMPDIR directory declared in ${OVEROTOP}/build/conf/site.conf.

TMPDIR defaults to ${OVEROTOP}/tmp, but you can point it somewhere else.

For instance, putting TMPDIR on a faster disk can speed your build.

Makefile

Create a makefile for your project pointing to the cross-build toolchain.

Here is a simple one for helloworld.

# Makefile for building with the OE cross tools 
#
# OVEROTOP is normally ${HOME}/overo-oe 
#
# OETMP is the same as TMPDIR as defined in ${OVEROTOP}/build/conf/site.conf
#

OETMP = ${OVEROTOP}/tmp

TOOLDIR = ${OETMP}/cross/armv7a/bin

STAGEDIR = ${OETMP}/staging/armv7a-angstrom-linux-gnueabi/usr

CC = ${TOOLDIR}/arm-angstrom-linux-gnueabi-gcc

CFLAGS = -Wall  

LIBDIR = ${STAGEDIR}/lib

INCDIR = ${STAGEDIR}/include      

LIBS = -L ${LIBDIR}

TARGET = helloworld

OBJS = helloworld.o 


${TARGET} : $(OBJS)
        ${CC} ${CFLAGS} ${OBJS} ${LIBS} -o ${TARGET}

helloworld.o: helloworld.c 
        ${CC} ${CFLAGS} -I ${INCDIR} -c helloworld.c  

clean:
        rm -f ${TARGET} ${OBJS} *~

Distribute

Copy the resulting target executable to the overo.

1. If you are using a microSD card, copy your executable to the rootfs before you unmount it in the final step.

2. If you have a network connection to the overo, use scp.

3. If you have a kermit console session, use the kermit SEND command.

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