Add formal specification of what c_strtod, c_strtold do.

diff --git a/ChangeLog b/ChangeLog
index 42c3aca..f8fc16f 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+2009-01-24  Bruno Haible  <bruno@clisp.org>
+
+       * lib/c-strtod.h (c_strtod, c_strtold): Add specification.
+
 2009-01-23  Bruno Haible  <bruno@clisp.org>
 
        Make c-strtod, c-strtold usable in libraries.

diff --git a/lib/c-strtod.h b/lib/c-strtod.h
index ca9a9e7..4458d67 100644 (file)
--- a/lib/c-strtod.h
+++ b/lib/c-strtod.h
@@ -1,2 +1,37 @@
-double c_strtod (char const *, char **);
-long double c_strtold (char const *, char **);
+/* Convert string to double, using the C locale.
+
+   Copyright (C) 2003-2004, 2009 Free Software Foundation, Inc.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+/* Parse the initial portion of the string pointed to by NPTR as a floating-
+   point number (in decimal or hexadecimal notation), like in the C locale:
+   accepting only the ASCII digits '0'..'9', and only '.' as decimal point
+   character.
+   If ENDPTR is not NULL, set *ENDPTR to point to the first byte beyond the
+   parsed number or to NPTR if the string does not start with a parseable
+   number.
+   Return value:
+   - If successful, return the value as a double or 'long double',
+     respectively, and don't modify errno.
+   - In case of overflow, return ±HUGE_VAL or ±HUGE_VALL, respectively, and
+     set errno to ERANGE.
+   - In case of underflow, return a value very near to 0 and set errno to
+     ERANGE.
+   - If the string does not start with a number at all, return 0 (and recall
+     that if ENDPTR != NULL, *ENDPTR is set to NPTR).
+   - In case of other error, return 0 and set errno, for example to EINVAL
+     or ENOMEM.  */
+extern double      c_strtod  (char const *nptr, char **endptr);
+extern long double c_strtold (char const *nptr, char **endptr);