Hey Asma, yes, in older versions of gcc generator tools like flex/bison were used to parse the source code, but this was changed with newer versions. Now, GCC uses hand-written lexer and parsers (recursive descent parser). So for C, you need to look for gcc-x.y.z/gcc/c-parser.c. Hope that helps, Andi ----- Original Message ----- From: "charfi asma" <charfiasma@xxxxxxxx> To: gcc-help@xxxxxxxxxxx Sent: Monday, July 25, 2011 1:54:23 PM Subject: gcc analyze tools Hello, to analyze the source code, I thought that gcc uses flex and bison. but I red yesterday in a presentation done on 2008 that gcc did not use those old tools. I tried to verify and I find that for c++ in the cp directory there is lex.c it means that gcc still use flex bison to parse source code; did someone has as better knowledges about gcc analysis and can give me a better idea about which tools are used by gcc to parse source code? thank you very much. Asma