Linux / glibc 2.8: ARG_MAX undeclard?

h2o_hyperic Sep 19, 2008 9:54 AM

Currently Being Moderated

Sigar is very cool and everything runs out of the box, so I wanted to rebuild from scratch and maybe provide a Gentoo package. But not so fast cowboy:

       [cc] /tmp/hyperic-sigar-1.6.0-src/src/os/linux/linux_sigar.c: In function 'sigar_proc_env_get':
       [cc] /tmp/hyperic-sigar-1.6.0-src/src/os/linux/linux_sigar.c:889: error: 'ARG_MAX' undeclared (first use in this function)

This looks interesting, because limits.h pulls in sys/params.h which includes linux/limits.h and then successfully UNdefines ARG_MAX again because it thinks it knows better:

--snip--

#ifndef ARG_MAX
# define __undef_ARG_MAX
#endif

#include limits.h
#include linux/limits.h
#include linux/param.h

/* The kernel headers defines ARG_MAX.  The value is wrong, though.  */
#ifndef __undef_ARG_MAX
# undef ARG_MAX
# undef __undef_ARG_MAX
#endif

--snip--

..and so I end up with no ARG_MAX. I know that directly defining values from linux/* is bad, but in this case it looks like a valid workaround. Sure enough, adding the following after all includes:

#ifndef ARG_MAX
#define ARG_MAX 131072
#endif

..fixes things to build & run fine, as expected.

This is with glibc 2.8_p20080602 - arguably a "testing" version, but since this is Gentoo practically everything is built from source, and this is the very first time I ran into this particular error.

Any other suggestions? Should I file this into JIRA?

thanks for an awesome package,
Holger

fixed include brackets

   
Message was edited by: h2o