I found that gcc-4 from a recent setup.exe could not start cc1 because the latter could not find some shared object file.
I confirmed that by running cc1 alone with an empty PATH variable. > $ ( export PATH= ; /cygdrive/c/cygwin/bin/gcc-4.exe -v -E - < /dev/null ) > Using built-in specs. > COLLECT_GCC=/cygdrive/c/cygwin/bin/gcc-4 > COLLECT_LTO_WRAPPER=/cygdrive/c/cygwin/bin/../lib/gcc/i686-pc-cygwin/4.5.3/lto-wrapper.exe > Target: i686-pc-cygwin > Configured with: > /gnu/gcc/releases/respins/4.5.3-3/gcc4-4.5.3-3/src/gcc-4.5.3/configure > --srcdir=/gnu/gcc/releases/respins/4.5.3-3/gcc4-4.5.3-3/src/gcc-4.5.3 > --prefix=/usr --exec-prefix=/usr --bindir=/usr/bin --sbindir=/usr/sbin > --libexecdir=/usr/lib --datadir=/usr/share --localstatedir=/var > --sysconfdir=/etc --datarootdir=/usr/share --docdir=/usr/share/doc/gcc4 -C > --datadir=/usr/share --infodir=/usr/share/info --mandir=/usr/share/man -v > --with-gmp=/usr --with-mpfr=/usr --enable-bootstrap > --enable-version-specific-runtime-libs --libexecdir=/usr/lib --enable-static > --enable-shared --enable-shared-libgcc --disable-__cxa_atexit --with-gnu-ld > --with-gnu-as --with-dwarf2 --disable-sjlj-exceptions > --enable-languages=ada,c,c++,fortran,java,lto,objc,obj-c++ --enable-graphite > --enable-lto --enable-java-awt=gtk --disable-symvers --enable-libjava > --program-suffix=-4 --enable-libgomp --enable-libssp --enable-libada > --enable-threads=posix --with-arch=i686 --with-tune=generic --enable-libgcj-sublibs CC=gcc-4 CXX=g++-4 CC_FOR_TARGET=gcc-4 CXX_FOR_TARGET=g++-4 GNATMAKE_FOR_TARGET=gnatmake GNATBIND_FOR_TARGET=gnatbind --with-ecj-jar=/usr/share/java/ecj.jar > Thread model: posix > gcc version 4.5.3 (GCC) > COLLECT_GCC_OPTIONS='-v' '-E' '-mtune=generic' '-march=i686' > /cygdrive/c/cygwin/bin/../lib/gcc/i686-pc-cygwin/4.5.3/cc1.exe -E -quiet -v >-iprefix /cygdrive/c/cygwin/bin/../lib/gcc/i686-pc-cygwin/4.5.3/ >-D__CYGWIN32__ -D__CYGWIN__ -Dunix -D__unix__ -D__unix -idirafter >/usr/lib/../include/w32api -idirafter ../../include/w32api - -mtune=generic >-march=i686 > /usr/lib/gcc/i686-pc-cygwin/4.5.3/cc1.exe: error while loading shared > libraries: ?: cannot open shared object file: No such file or directory > > $ /usr/lib/gcc/i686-pc-cygwin/4.5.3/cc1.exe -o /dev/null - < /dev/null > > Analyzing compilation unit > Performing interprocedural optimizations > <*free_lang_data> <visibility> <early_local_cleanups> <whole-program> ><inline>Assembling functions: > > Execution times (seconds) > TOTAL : 0.00 0.00 >0.01 590 kB > > $ PATH= /usr/lib/gcc/i686-pc-cygwin/4.5.3/cc1.exe -o /dev/null - < /dev/null > /usr/lib/gcc/i686-pc-cygwin/4.5.3/cc1.exe: error while loading shared > libraries: ?: cannot open shared object file: No such file or directory Cheers! -- -- Problem reports: http://cygwin.com/problems.html FAQ: http://cygwin.com/faq/ Documentation: http://cygwin.com/docs.html Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple

