[Bug fortran/96486] get_environment_variable crashes for environment variables that are empty strings

[sgk at troutmask dot apl.washington.edu]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96486

--- Comment #26 from Steve Kargl <sgk at troutmask dot apl.washington.edu> ---
On Fri, Aug 07, 2020 at 09:55:06PM +0000, schwab@linux-m68k.org wrote:
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96486
> 
> --- Comment #25 from Andreas Schwab <schwab@linux-m68k.org> ---
> But why does it error out?  It shouldn't!
> 

You'll have to ask Paul Brook why he chose to issue an error.

% svn annotate libgfortran/intrinsic/env.c
...
 85656     pbrook   if (value != NULL)
 85656     pbrook     { 
 85656     pbrook       if (value_len < 1)
 85656     pbrook       runtime_error ("Zero-length string passed as value to "
 85656     pbrook                      "get_environment_variable.");
 85656     pbrook       else
 85656     pbrook       memset (value, ' ', value_len); /* Blank the string. 
*/
 85656     pbrook     }

IIRC, r85656 is tree-ssa becoming pre-gcc 4.0.0.