[lmi-commits] [lmi] master 379fcf3 4/4: Change lmi::ssize_t to accommodate LP64

[Greg Chicares]

branch: master
commit 379fcf316228d9806340079457e295a6e8ccc91b
Author: Gregory W. Chicares <address@hidden>
Commit: Gregory W. Chicares <address@hidden>

    Change lmi::ssize_t to accommodate LP64
    
    See:
      https://lists.nongnu.org/archive/html/lmi/2018-11/msg00019.html
---
 ssize_lmi.hpp      | 8 +++++++-
 ssize_lmi_test.cpp | 5 +++--
 2 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/ssize_lmi.hpp b/ssize_lmi.hpp
index a400e8b..a05462a 100644
--- a/ssize_lmi.hpp
+++ b/ssize_lmi.hpp
@@ -36,6 +36,12 @@
 ///   numeric_limits<std::make_signed_t<std::size_t>>::max()
 /// . Throws, or fails to compile, if violated.
 ///
+/// Type lmi::ssize_t is simply 'int'. An earlier version had used
+///   using ssize_t = std::make_signed_t<std::size_t>;
+/// but that is 'long int' for LP64:
+///   https://lists.nongnu.org/archive/html/lmi/2018-11/msg00006.html
+/// whereas 'int' is preferred as explained below.
+///
 /// Motivation: to avoid error-prone mixing of signed and unsigned.
 ///
 ///   https://github.com/ericniebler/stl2/issues/182
@@ -85,7 +91,7 @@
 
 namespace lmi
 {
-using ssize_t = std::make_signed_t<std::size_t>;
+using ssize_t = int;
 
 template<typename Container>
 constexpr ssize_t ssize(Container const& c)
diff --git a/ssize_lmi_test.cpp b/ssize_lmi_test.cpp
index d367db5..a92a31f 100644
--- a/ssize_lmi_test.cpp
+++ b/ssize_lmi_test.cpp
@@ -62,7 +62,7 @@
 ///
 /// and the compiler should emit a diagnostic if an array with more
 /// than SCHAR_MAX elements is passed. Because the standard does not
-/// specify this precisely, it seems best to use type std::size_t for
+/// specify this precisely, it seems best to use a deduced type for
 /// array-bound template parameters and convert their values to the
 /// desired return type using a facility such as bourn_cast or a
 /// braced-init-list that ensures value preservation.
@@ -92,7 +92,8 @@
 /// might specify std::size_t for the non-type parameter, especially
 /// in light of the [temp.deduct.type] quote above, but it seems even
 /// better to use auto, again as in f0g(), and to specify the return
-/// type of lmi::ssize() as the signed analogue of std::size_t.
+/// type of lmi::ssize() as lmi::ssize_t (which is the signed analogue
+/// of std::size_t for 32-bit architectures, but not for LP64, e.g.).
 
 namespace experimental
 {