This module depends on the availability of the system call setenv. This is *not* defined in ANSI-C (getenv() is; setenv() is not) and therefore might fail for various reasons on different platforms. Note that the plotting/imaging functionality can be easily switched off by setting the plotting/imaging commands to 'no'.
If a plotting call fails for 'external' reasons (i.e. when communication with the external process), a warning message is printed, but success status is returned. A failure exit status is returned only in cases of invalid input (null pointers etc.).
1.4.6