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-rw-r--r--Modules/_io/_iomodule.h13
1 files changed, 12 insertions, 1 deletions
diff --git a/Modules/_io/_iomodule.h b/Modules/_io/_iomodule.h
index 1aa10b3..b621c51 100644
--- a/Modules/_io/_iomodule.h
+++ b/Modules/_io/_iomodule.h
@@ -70,6 +70,14 @@ PyAPI_DATA(PyObject *) PyExc_BlockingIOError;
* Offset type for positioning.
*/
+/* Printing a variable of type off_t correctly and without producing
+ compiler warnings is surprisingly painful. We identify an integer
+ type whose size matches off_t and then: (1) cast the off_t to that
+ integer type and (2) use the appropriate conversion specification
+ for printf. The cast is necessary: gcc complains about formatting
+ a long with "%lld" even when both long and long long have the same
+ precision. */
+
#if defined(MS_WIN64) || defined(MS_WINDOWS)
/* Windows uses long long for offsets */
@@ -79,7 +87,7 @@ typedef PY_LONG_LONG Py_off_t;
# define PY_OFF_T_MAX PY_LLONG_MAX
# define PY_OFF_T_MIN PY_LLONG_MIN
# define PY_PRIdOFF "lld" /* format to use in printf with type off_t */
-
+# define PY_OFF_T_COMPAT long long /* standard type compatible with off_t */
#else
/* Other platforms use off_t */
@@ -90,18 +98,21 @@ typedef off_t Py_off_t;
# define PY_OFF_T_MAX PY_LLONG_MAX
# define PY_OFF_T_MIN PY_LLONG_MIN
# define PY_PRIdOFF "lld"
+# define PY_OFF_T_COMPAT long long
#elif (SIZEOF_OFF_T == SIZEOF_LONG)
# define PyLong_AsOff_t PyLong_AsLong
# define PyLong_FromOff_t PyLong_FromLong
# define PY_OFF_T_MAX LONG_MAX
# define PY_OFF_T_MIN LONG_MIN
# define PY_PRIdOFF "ld"
+# define PY_OFF_T_COMPAT long
#elif (SIZEOF_OFF_T == SIZEOF_SIZE_T)
# define PyLong_AsOff_t PyLong_AsSsize_t
# define PyLong_FromOff_t PyLong_FromSsize_t
# define PY_OFF_T_MAX PY_SSIZE_T_MAX
# define PY_OFF_T_MIN PY_SSIZE_T_MIN
# define PY_PRIdOFF "zd"
+# define PY_OFF_T_COMPAT Py_ssize_t
#else
# error off_t does not match either size_t, long, or long long!
#endif