The inclusion of iostream breaks the following program. A workaround is to define an inline function that calls into tolower() and use it as the last argument to transform().
Code: #include <cctype> #include <string> #include <algorithm> #include <iostream> int main() { std::string foo("AbCd"); std::transform(foo.begin(), foo.end(), foo.begin(), std::tolower); return 0; } Output: Reading specs from /usr/local/lib/gcc/i686-pc-linux-gnu/3.4.4/specs Configured with: ../gcc-3.4.4/configure --prefix=/usr/local --enable-languages=c++ Thread model: posix gcc version 3.4.4 /usr/local/libexec/gcc/i686-pc-linux-gnu/3.4.4/cc1plus -E -quiet -v -D_GNU_SOURCE foo.cpp -mtune=pentiumpro -o foo.ii ignoring nonexistent directory "/usr/local/lib/gcc/i686-pc-linux-gnu/3.4.4/../../../../i686-pc-linux-gnu/include" #include "..." search starts here: #include <...> search starts here: /usr/local/lib/gcc/i686-pc-linux-gnu/3.4.4/../../../../include/c++/3.4.4 /usr/local/lib/gcc/i686-pc-linux-gnu/3.4.4/../../../../include/c++/3.4.4/i686-pc-linux-gnu /usr/local/lib/gcc/i686-pc-linux-gnu/3.4.4/../../../../include/c++/3.4.4/backward /usr/local/include /usr/local/lib/gcc/i686-pc-linux-gnu/3.4.4/include /usr/include End of search list. /usr/local/libexec/gcc/i686-pc-linux-gnu/3.4.4/cc1plus -fpreprocessed foo.ii -quiet -dumpbase foo.cpp -mtune=pentiumpro -auxbase foo -version -o foo.s GNU C++ version 3.4.4 (i686-pc-linux-gnu) compiled by GNU C version 3.4.4. GGC heuristics: --param ggc-min-expand=99 --param ggc-min-heapsize=129426 foo.cpp: In function `int main()': foo.cpp:12: error: no matching function for call to `transform(__gnu_cxx::__normal_iterator<char*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, __gnu_cxx::__normal_iterator<char*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, __gnu_cxx::__normal_iterator<char*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, <unknown type>)' -- Summary: including iostream causes lookup of std function to fail when passed into STL algorithm Product: gcc Version: 3.4.4 Status: UNCONFIRMED Severity: normal Priority: P2 Component: c++ AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: jbeardsley at ncaustin dot com CC: gcc-bugs at gcc dot gnu dot org GCC host triplet: i686-pc-linux-gnu http://gcc.gnu.org/bugzilla/show_bug.cgi?id=22070