On Fri, Sep 28, 2007 at 11:14:00PM +0100, Stefan Schulze Frielinghaus wrote: > I'm trying to port a tool from solaris 10 to Fedora 7. While running gcc > I get some strange errors. Example app: > > include <netinet/in.h> > > int main() { > const int segments = 100; > inet6_rth_space(IPV6_RTHDR_TYPE_0, segments); > > return 0; > } > > While running gcc the following output is created: > > > $ gcc -Wall -o test test.c > > test.c: In function ‘main’: > > test.c:5: warning: implicit declaration of function ‘inet6_rth_space’ > > Under solaris it compiles just fine. Does someone know whats wrong? This function is an extension, isn't part of e.g. SuS, current POSIX, etc. If you compile with -D_GNU_SOURCE, it will be enabled. For more info run info libc 'Feature Test Macros' Jakub