12 Using a different C compiler

The Mercury compiler takes special advantage of certain extensions provided by GNU C to generate much more efficient code. We therefore recommend that you use GNU C for compiling Mercury programs. However, if for some reason you wish to use another compiler, it is possible to do so. Here is what you need to do.

• Create a new configuration for the Mercury system using the ‘mercury_config’ script, specifying the different C compiler, e.g. ‘mercury_config --output-prefix=/usr/local/mercury-cc --with-cc=cc’.
• Add the ‘bin’ directory of the new configuration to the beginning of your PATH.
• You must use a grade beginning with ‘none’ or ‘hlc’ (e.g. ‘hlc.gc’). You can specify the grade in one of three ways: by setting the MERCURY_DEFAULT_GRADE environment variable, by adding a line ‘GRADE=…’ to your ‘Mmake’ file, or by using the ‘--grade’ option to ‘mmc’. (You will also need to install those grades of the Mercury library, if you have not already done so.)
• If your compiler is particularly strict in enforcing ANSI compliance, you may also need to compile the Mercury code with ‘--no-static-ground-terms’.