IMSL C Library

Because there can be undesirable interaction between the environment variables that you need to set up for IMSL and other tasks, do your IMSL computations via a separate window.
```
         % xterm &
```
That is, do all you IMSL computations in the xterm window that you open with the xterm command. For example if you use vi to edit, and you try to edit your source file in the same window you define the IMSL environment variables, you will get an error.
Define the necessary environment variables for C (and for Fortran) by sourcing the iptsetup.csh file via
```
         % source /opt/lib/ipt_2.0/ipt/bin/iptsetup.csh
```

Now you can compile and execute. To compile,

         % cc yourcprogram.c -o yourexecutable $LINK_CNL $CFLAGS

         % yourexecutable

Example, using the IMSL example program, "cmath.c" available at /opt/lib/ipt_2.0/examples/cnl

           [7]% cp /opt/lib/ipt_2.0/examples/cnl/cmath.c .
           [8]% source /opt/lib/ipt_2.0/ipt/bin/iptsetup.csh
           [9]% cc cmath.c -o cmath.exe $CFLAGS $LINK_CNL
           [10]% cmath.exe
             Library version:  IMSL C/Math/Library Version 2.0
             Customer number:  601350

             Solution, x of Ax = b
             1           2           3
            -2          -2           3

         where the first line, "1     2      3" refers to 
          x   x    x
           1   2    3