[Bug fortran/32021] New: Fix,document,remove GFORTRAN_* environment variables

["burnus at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>]

The following environment variables exist in gfortran (inherited from g95, cf.
http://ftp.g95.org/G95Manual.pdf). They are not documented and don't seem to
work, however they are partially implemented.

GFORTRAN_FPU_PRECISION can probably be removed (cf. -mpc32, -mpc64  and -mpc80)
GFORTRAN_MEM_INIT sounds something which should be handled by the front end (w/
a flag) for speed reasons. (cf. -finit-local-zero, PR20441).
Similar for GFORTRAN_MEM_CHECK.

GFORTRAN_SIG* could be implemented, if someone needs it. (can be done via the
signal vendor intrinsic).

GFORTRAN_FPU_ROUND etc. could be handled by the Fortran 2003 IEEE rounding
modes - or is this environment variable needed?

--- gfortran.texi       (Revision 124895)
+++ gfortran.texi       (Arbeitskopie)
@@ -604,6 +612,51 @@
 when @command{a.out} is the compiled Fortran program that you want to run.
 Default is a single space.

+@node GFORTRAN_MEM_INIT
+@section @env{GFORTRAN_MEM_INIT}---Default initialization of allocated memory
+
+This environment variable specifies how allocated memory is initialized.
+Default value is @samp{NONE} for no initialization (faster); other options
+are @samp{NAN} for not-a-number with mantissa @samp{0x40f95} or
+a custom hexadecimal value.
+
+@node GFORTRAN_MEM_CHECK
+@section @env{GFORTRAN_MEM_CHECK}---Default initialization of allocated memory
+
+If the first letter is @samp{y}, @samp{Y} or @samp{1}, memory which is still
+allocated when the program ends is reported; it is not reported if the first
+letter is @samp{n}, @samp{N} or @samp{0}. Default is not to report.
+
+@node GFORTRAN_SIGHUP
+@section @env{GFORTRAN_SIGHUP}---Behavior on SIGHUP
+
+When the @env{GFORTRAN_SIGHUP} variable is set to @samp{IGNORE}, the signal
+SIGHUP is ignored. It it is set to @samp{ABORT}, the program aborts.
+Default is to abort.
+
+@node GFORTRAN_SIGINT
+@section @env{GFORTRAN_SIGINT}---Behavior on SIGINT
+
+When the @env{GFORTRAN_SIGINT} variable is set to @samp{IGNORE}, the signal
+SIGINT is ignored. It it is set to @samp{ABORT}, the program aborts.
+Default is to abort.
+
+@node GFORTRAN_FPU_ROUND
+@section @env{GFORTRAN_FPU_ROUND}---Floating point rounding
+
+The @env{GFORTRAN_FPU_ROUND} variable specifies the floating point
+rounding. Possible values are: to round to the @samp{NEAREST}
+integer, to always round @samp{UP}, to always round @samp{DOWN},
+or to round always towards @samp{ZERO}. Default is to round
+to the nearest integer.
+
+@node GFORTRAN_FPU_PRECISION
+@section @env{GFORTRAN_FPU_PRECISION}---Precision of intermediate results
+
+The @env{GFORTRAN_FPU_PRECISION} variable specifies the precision
+of intermediate results. Possible values are
+@samp{24}, @samp{53} and @samp{64}. Default is @samp{64}.
+
 @node GFORTRAN_CONVERT_UNIT
 @section @env{GFORTRAN_CONVERT_UNIT}---Set endianness for unformatted I/O


-- 
           Summary: Fix,document,remove GFORTRAN_* environment variables
           Product: gcc
           Version: 4.3.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: burnus at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32021