On 2021-05-06, aotto <aotto1968@xxxxxxxxxxx> wrote: > I want to write a "autoconf/automake" script for an application ONLY for > 32 bit on 64 bit Linux. > This meant that the default for configure must be 32 bit and nothing else. > > I know that a user can do "configure CC="gcc -m32"... etc but this is > NOT what I want. > I want that the 'configure' script set the 32bin once at start and fix. The general approach I would take to doing this in a configure script is something like this: Step 1) Figure out how you are going to determine whether the compiler and linker are producing the desired output format. This should be done in a portable way. Step 2) Use AC_LINK_IFELSE to compile a test program. In the "action-if-true" branch, check whether the linker output (which will be in the file called conftest$EXEEXT) is as expected. If that passes, you know that no special compiler options are required. Step 3) If your verification fails, you can then temporarily alter CFLAGS and/or LDFLAGS to test whatever combinations you think might work, then repeat the AC_LINK_IFELSE and verification procedures to see if they actually did work. Step 4) If a working method was found, then use AC_SUBST to substitute appropriate variables and use them in your build scripts. If no working method was found, use AC_MSG_FAILURE to report the error. I will add that for this purpose you may find that using AC_COMPUTE_INT (rather than AC_LINK_IFELSE) is more convenient when implementing your configure test. The overall structure is the same, however. Hope that helps, Nick
