Long live QString::asprintf()!

asprintf() is a GNU extension that prints into a string it
allocates internally. Arguably, that's a better name for
QString::sprintf() since it also allocates memory internally.

The main problem with QString::sprintf() isn't that it's
dangerous to use (it is), but that it's not static. It also
returns a reference instead of by-value, breaking RVO.

There is a comment about removing this function completely
in Qt 6.0, but it remains the only printf-style function
in Qt that can allocate the target string, so it's vital
for logging, e.g., and the recommended replacement code
(http://linux.die.net/man/3/vsnprintf) is a nightmare.

So this patch adds static (v)asprintf() methods to replace it.

Further patches will fix up all in-tree callers and finally
deprecate the old (v)sprintf().

Test coverage is provided through the existing tests of
sprintf(), which is implemented in terms of asprintf().

Arguably, the in-tree callers show that QByteArray would
benefit from having an asprintf(), too, as most of the
in-tree code works around its lack with calls
to to{Latin1,Local8Bit}() after using the QString version.

[ChangeLog][QtCore][QString] Added asprintf(), vasprintf().

Change-Id: I8510f8d67c22230653ec0f1c252c01bc95f3c386
Reviewed-by: Kai Koehne <kai.koehne@theqtcompany.com>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/src/widgets/itemviews/qitemdelegate.cpp b/src/widgets/itemviews/qitemdelegate.cpp
index 67b53c072c..cd952737dd 100644
--- a/src/widgets/itemviews/qitemdelegate.cpp
+++ b/src/widgets/itemviews/qitemdelegate.cpp
@@ -975,7 +975,7 @@ QPixmap QItemDelegate::decoration(const QStyleOptionViewItem &option, const QVar
     return qvariant_cast<QPixmap>(variant);
 }
 
-// hacky but faster version of "QString::sprintf("%d-%d", i, enabled)"
+// hacky but faster version of "QString::asprintf("%d-%d", i, enabled)"
 static QString qPixmapSerial(quint64 i, bool enabled)
 {
     ushort arr[] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, '-', ushort('0' + enabled) };