On 01/12/2010 07:19 AM, Ian Lance Taylor wrote:
> "Philip A. Prindeville" <philipp_subx@xxxxxxxxxxxxxxxxxxxxx> writes:
>
>> * how (on a somewhat hinky, tweaked compiler) do I figure out where it looks for system headers by default?
>
> gcc -v will show you this when compiling a file.
>
>> * and when additional arguments get added (--sysroot, -isysroot, -isystem, -iquote, etc) how do I figure out where the compiler is looking for headers and libraries (short of "strace -f -e trace=open,stat,fstat,lstat,access gcc ...")?
>
> Same answer.
>
> Ian
Ok, so I'm invoking the compiler as:
$ /home/philipp/kernel/build_i586/staging_dir/bin/i586-linux-uclibc-gcc -Os -pipe -fomit-frame-pointer -march=k6-2 -fno-align-functions -fno-align-loops -fno-align-jumps -fno-align-labels --sysroot=/home/philipp/kernel/build_i586/staging_dir -isystem /usr/include -Wall -O2 -D_REENTRANT -fPIC -Isrc/include -I/usr/include/openssl -I- '-DPROXY_VERSION="NOVER"' '-DCDIR="/etc"' '-DCFILE="astmanproxy.conf"' '-DMDIR="/usr/lib/astmanproxy/modules"' '-DPDIR="/etc/asterisk"' '-DPFILE="astmanproxy.users"' -cb -o ssl.o src/ssl.c -v
and it's telling me:
...
gcc version 4.2.5 20090325 (prerelease)
/home/philipp/kernel/build_i586/staging_dir/bin-ccache/../libexec/gcc/i586-linux-uclibc/4.2.5/cc1 -quiet -v -Isrc/include -I/usr/include/openssl -I- -iprefix /home/philipp/kernel/build_i586/staging_dir/bin-ccache/../lib/gcc/i586-linux-uclibc/4.2.5/ -isysroot /home/philipp/kernel/build_i586/staging_dir -D_REENTRANT -DPROXY_VERSION="NOVER" -DCDIR="/etc" -DCFILE="astmanproxy.conf" -DMDIR="/usr/lib/astmanproxy/modules" -DPDIR="/etc/asterisk" -DPFILE="astmanproxy.users" -isystem /usr/include src/ssl.c -quiet -dumpbase ssl.c -march=k6-2 -auxbase ssl -Os -O2 -Wall -version -fomit-frame-pointer -fno-align-functions -fno-align-loops -fno-align-jumps -fno-align-labels -fPIC -o - |
/home/philipp/kernel/build_i586/staging_dir/bin-ccache/../lib/gcc/i586-linux-uclibc/4.2.5/../../../../i586-linux-uclibc/bin/as -V -Qy -o /tmp/ccTjdxIN.o -
GNU assembler version 2.17.50.0.14 (i586-linux-uclibc) using BFD version (Linux/GNU Binutils) 2.17.50.0.14.20070322
cc1: note: obsolete option -I- used, please use -iquote instead
ignoring duplicate directory "/home/philipp/kernel/build_i586/staging_dir/lib/gcc/i586-linux-uclibc/4.2.5/include"
ignoring duplicate directory "/home/philipp/kernel/build_i586/staging_dir/lib/gcc/i586-linux-uclibc/4.2.5/../../../../i586-linux-uclibc/sys-include"
ignoring duplicate directory "/home/philipp/kernel/build_i586/staging_dir/lib/gcc/i586-linux-uclibc/4.2.5/../../../../i586-linux-uclibc/include"
#include "..." search starts here:
src/include
/usr/include/openssl
#include <...> search starts here:
/usr/include
/home/philipp/kernel/build_i586/staging_dir/bin-ccache/../lib/gcc/i586-linux-uclibc/4.2.5/include
/home/philipp/kernel/build_i586/staging_dir/bin-ccache/../lib/gcc/i586-linux-uclibc/4.2.5/../../../../i586-linux-uclibc/sys-include
/home/philipp/kernel/build_i586/staging_dir/bin-ccache/../lib/gcc/i586-linux-uclibc/4.2.5/../../../../i586-linux-uclibc/include
End of search list.
My question is, why is it saying:
#include <...> search starts here:
/usr/include
and not applying the --sysroot argument to look for /sysroot-prefix/usr/include instead?
If I specify -isystem /usr/include then it doesn't find the appropriate files.
If I specify -isystem /home/philipp/kernel/build_i586/staging_dir/usr/include then it does.
This contradicts what the man page says the --sysroot argument does:
--sysroot=dir
Use dir as the logical root directory for headers and libraries.
For example, if the compiler would normally search for headers in
/usr/include and libraries in /usr/lib, it will instead search
dir/usr/include and dir/usr/lib.
If you use both this option and the -isysroot option, then the
--sysroot option will apply to libraries, but the -isysroot option
will apply to header files.
Using -isysroot yields the same.
