[Bug libfortran/53051] New: I/O: Support reading floating-point numbers which use "Q" for the exponent

[burnus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53051

             Bug #: 53051
           Summary: I/O: Support reading floating-point numbers which use
                    "Q" for the exponent
    Classification: Unclassified
           Product: gcc
           Version: 4.8.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libfortran
        AssignedTo: unassig...@gcc.gnu.org
        ReportedBy: bur...@gcc.gnu.org
                CC: jvdeli...@gcc.gnu.org


gfortran supports since GCC 4.6 quadprecision on common hardware. Thus, users
started to expect that "q" works for the exponents, e.g., 4.0q0. (The "q" is a
vendor extension.)

In 4.7, the "q" became supported in the source code (with -Wreal-q-constant as
warning). Well, it seems as if we should to also support "q" in the library.

Cf. https://groups.google.com/forum/#!topic/comp.lang.fortran/rfDXj9VQRZM


Untested draft patch below.

--- a/libgfortran/io/list_read.c
+++ b/libgfortran/io/list_read.c
@@ -1138,2 +1138,4 @@ parse_real (st_parameter_dt *dtp, void *buffer, int
length)
        case 'D':
+       case 'q':
+       case 'Q':
          push_char (dtp, 'e');
@@ -1451,2 +1453,4 @@ read_real (st_parameter_dt *dtp, void * dest, int length)
        case 'd':
+       case 'Q':
+       case 'q':
          goto exp1;
@@ -1548,2 +1552,4 @@ read_real (st_parameter_dt *dtp, void * dest, int length)
        case 'd':
+       case 'Q'
+       case 'q':
          goto exp1;
diff --git a/libgfortran/io/read.c b/libgfortran/io/read.c
index aa41bc7..32c8b32 100644
--- a/libgfortran/io/read.c
+++ b/libgfortran/io/read.c
@@ -1028,2 +1028,4 @@ found_digit:
        case 'D':
+       case 'q':
+       case 'Q':
          ++p;