David,

On 22 August 2017 at 04:53, David C. Rankin
[off-list ref] wrote:

All,

  The man 3 dlopen example needs updating to run on x86_64. It will run fine
as a 32-bit compile (with -m32), but fails without it, e.g.

$ gcc -Wall -Wextra -pedantic -Wshadow -std=gnu11 -Ofast -ldl -o
bin/dlopen_man_ex dlopen_man_ex.c

$ ./bin/dlopen_man_ex
/usr/lib/libm.so: invalid ELF header

  While limiting the target to 32-bit works as advertised:

$ gcc -Wall -Wextra -pedantic -Wshadow -m32 -std=gnu11 -Ofast -ldl -o
bin/dlopen_man_ex dlopen_man_ex.c

$ ./bin/dlopen_man_ex
-0.416147

  This behavior is confirmed both on openSuSE and Archlinux with

gcc (GCC) 7.1.1 20170630 (on Archlinux with multilib support)

  I'm not exactly sure where in the compile and library search the problem
with the example is, but explicitly specifying /usr/lib64/libm.so doesn't
change the error on x86_64. Whether this is a libdl problem? It may be
something simple I'm just being dense about, but I thought I would pass this
along for verification and correction, if required.

Can you show the source code of the example that you are using that
doesn't work. I wonder if you may be looking at an old version of the
manual page.

Cheers,

Michael

-- 
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/
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