SlackBuilds.org/development/qt-creator

Qt Creator is a Cross-Platform Qt IDE.

The goal of Qt Creator is to provide a cross-platform,
complete Integrated Development Environment (IDE) to develop
Qt projects.

NOTES:
1 - This package conflicts with qt-creator2: install
only one of the two.

2 - This version of Qt Creator is advised for Qt5.

3 - Before start building/editing your application, you
should configure the Qt kits (both Qt4 and Qt5).

4 - QmlDesigner will work properly only if you configure the
Qt5 Kit properly (Tools->Options->Build & Run->Kits) and
make it the Default Kit.

5 - An old IDE configuration in user home directory
(.config/QtProject*) also can lead to strange behavior.

6 - Examples, Qt5 docs and tutorials are not part of this
package (except for Qt Creator Docs itself).
To build Qt5 with documentations and examples do as
follow:
EXAMPLES=yes DOCS=yes ./qt5.SlackBuild

7 - Clang Code Model requires a newer LLVM version compared
to the official Slackware package. This SlackBuild can
build the required LLVM version and ship this plugin.
Note that the default option is disabled and enabling
Code Model option will significantly increase the build
time. To build Code Model plugin do as follow:
CODE_MODEL=yes ./qt-creator.SlackBuild