Ian, sorry I think this option (-D) can be useful. But I did not understand how to use this option . You told me to create a new file, but this file is for the GCC or for the program being compiled? Using the -D option, I can access the IP address within the compiled program or just during compilation? Thank you for your attention Harry 2011/8/5 Ian Lance Taylor <iant@xxxxxxxxxx>: > Harry Trinta <harrytpc@xxxxxxxxx> writes: > >> I'm developing a mechanism in the gcov, instead of writing the file >> gcda (in file gcov-io.c), it sends the information to a host via a >> socket. The host generates gcda. >> >> So I'd like to get the IP at compile time to use when sending the data >> through the socket. >> >> But from what you said, the variable is only available at compile >> time, which is not my case. >> >>> To be clear, this will give you a new variable in the compiler itself. >>> It will not give you a variable in the gcov program, nor in the program >>> you are compiling. You will have to figure out some mechanism to get >>> the value to the point where you need it. It's not clear to me where >>> that point is. >> >> What kinds of mechanisms I can develop to use this variable when >> sending information? > > There are many ways to get an IP address defined at compile time into > the gcov library. Most of them do not involve changing the compiler > proper at all (you do of course have to change the gcov support > library). > > Making this a compile time option seems odd. What should happen if you > link together two different files compiled with different values for the > option? What you really want is to make a link time option. > > Suppose you just change the gcov library to look for a global variable > gcov_ip_address. Then create a tiny file > > const char* gcov_ip_address = GCOV_IP_ADDRESS > > Then compile that file with -DGCOV_IP_ADDRESS=nn.nn.nn.nn. > > That approach is much simpler than changing the compiler proper. What > do you need that you can't get from that? > > Ian >
