Juergen Gotteswinter wrote:

perhaps linux32 helps you out

man linux32

thanks Juergen. that seems to set the environment for the program that is to be run, e.g. make, gcc, ld, etc. Not so much the environment where the target will run. roger wells

greetings

Juergen

Roger K. Wells wrote:

...

We develop software and are beginning a slow transition from 32 bit applications to their 64 bit equivalents. During this period it will be necessary to build programs targeted for both environments using the x86-64 machines for development.

here is a simple/small "application", sizes.c:

#include <stdio.h> #include <stdlib.h>

int main(int argc, char **argv) { printf("Various sizes:\n"); printf(" short = %d\n", sizeof(short)); printf(" int = %d\n", sizeof(int)); printf(" long = %d\n", sizeof(long)); printf(" float = %d\n", sizeof(float)); printf(" double = %d\n", sizeof(double)); return 0; }

if I build it using:

gcc -m32 -Wall -osizes sizes.c

there are no warnings or complaints and a functioning 32 bit program runs, giving the size of a long as 4 bytes. (Of course without the m32 flag the size of long is 8 bytes.)

if I try to do the equivalent in two steps:

gcc -c -m32 -Wall sizes.c gcc -osizes -Wl,-m,elf_i386 sizes.o

the result is: /usr/bin/ld: skipping incompatible /usr/lib/gcc/x86_64-redhat-linux/4.1.2/libgcc.a when searching for -lgcc /usr/bin/ld: skipping incompatible /usr/lib/gcc/x86_64-redhat-linux/4.1.2/libgcc.a when searching for -lgcc /usr/bin/ld: cannot find -lgcc collect2: ld returned 1 exit status

there is some confusion in the man pages as to whether the correct 32 bit emulation is elf_i386 or i386linux so:

gcc -osizes -Wl,-m,i386linux sizes.o gives result: /usr/bin/ld: unrecognized option '--eh-frame-hdr' /usr/bin/ld: use the --help option for usage information collect2: ld returned 1 exit status

since the single line command works it seems that there must be a way to get the job done. This becomes important when there are many source files and use of a traditional makefile is involved where compiling and linking are separate steps.

Thanks in advance for reading this, roger wells

---

CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos

You can always run VMware server or virtualbox and install a complete 32 bit system on the same host for a real build/test environment.

Don't forget about KVM. It just a yum install.

Neil

-- Neil Aggarwal, (281)846-8957, http://JAMMConsulting.com CentOS 5.4 VPS with unmetered bandwidth only $25/month! 7 day no risk trial! http://UnmeteredVPS.net for details.

Les Mikesell wrote:

Roger K. Wells wrote:

...

Juergen Gotteswinter wrote:

...

perhaps linux32 helps you out

man linux32

thanks Juergen. that seems to set the environment for the program that is to be run, e.g. make, gcc, ld, etc. Not so much the environment where the target will run.

You can always run VMware server or virtualbox and install a complete 32 bit system on the same host for a real build/test environment.

Thanks for the reply. That shouldn't be necessary since I can build 32 bit applications that work, just not with separate invocations of the compiler and linker. I think I must be missing appropriate flags to the linker, I just don't know what they are. roger wells