On Fri, 17 Oct 2008 11:11:21 -0700 (PDT) ann kok <[EMAIL PROTECTED]> wrote:
> hi all Hello, > why we have to put the following flags in the make.conf > > what are the purpose? > > CFLAGS="-O2 -pipe" > CXXFLAGS="-O2 -pipe" > CHOST="x86_64-pc-linux-gnu" These are parameters for the gcc compiler. On a Gentoo system, you compile all (or most of) your software from source, instead of simply installing a precompiled binary package, as in most other distributions. These parameters influence the compiler, the software which actually builds the program from the source code. Their exact meaning is documented in gcc's manual page (man gcc). -O2 instructs the compiler to perform second level optimizations on the code (note 'O', not '0'). -pipe tells gcc to use unix pipes for communication during the compile process, which might speed up things. CFLAGS specifies the options when compiling a C source file, CXXFLAGS is for C++ files. CHOST specifies your machine architecture and operating system type. This stems from the GNU config package which is used by the automake/autoconf build system which is used for most software. According to config.sub from autoconf, the format of this target specification is: # CPU_TYPE-MANUFACTURER-OPERATING_SYSTEM # or in some cases, the newer four-part form: # CPU_TYPE-MANUFACTURER-KERNEL-OPERATING_SYSTEM Cheers, Patric
