Qt5 qconfig.h weird - qt5

This is my context : I'm compiling a graphic engine using OpenGL on windows, so I included glext.h. Surprise, it is conflicting with gl2.h from Qt5 ..
I have found that gl2.h (from gles2) is included if QT_OPENGL_ES_2 is defined..
then I found that QT_OPENGL_ES_2 is defined by default and I can't define QT_NO_OPENGL_ES_2 ... or maybe i don't understand how the following code is supposed to work (btw every block in my qconfig.h - the one from Qt5 msvc10 offline installer - looks like that) :
#if defined(QT_OPENGL_ES_2) && defined(QT_NO_OPENGL_ES_2)
# undef QT_OPENGL_ES_2
#elif !defined(QT_OPENGL_ES_2)
# define QT_OPENGL_ES_2
#endif
Maybe it is because i have not slept much but it seems weird.
But in the case QT_OPENGL_ES_2 is not defined and QT_NO_OPENGL_ES_2 is defined,
I'm pretty sure (with my 4 not sleeping neurones) that it goes in the second branch and defines QT_OPENGL_ES_2 ...
I would have written if I were them :
#if defined(QT_OPENGL_ES_2) && defined(QT_NO_OPENGL_ES_2)
# undef QT_OPENGL_ES_2
#elif !defined(QT_OPENGL_ES_2) && !defined(QT_NO_OPENGL_ES_2)
# define QT_OPENGL_ES_2
#endif
Thank you for your time :)

Yeah, that's the bug, and I've been struggling for several days until it came out. I corrected it and now it's running well, no conflicts.
https://bugreports.qt-project.org/browse/QTBUG-28821?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel

Related

Successful build of Kicad 4.0.6 in Linux Mageia 5 via fixing a wx-3.0 symbol

I have managed to build the Kicad 4.0.6 in Linux Mageia 5.1 with gcc version 4.9.2. I first manually fixed two wxWidgets 3.0.2 header files in the /usr/include/wx-3.0/wx/ directory: regex.h and features.h. Kicad then compiled successfully. With the native wx-3.0 headers, the compiler generated the error in pcbnew/netlist_reader.cpp due to the undefined variable wxRE_ADVANCED.
The features.h header checks if the macro WX_NO_REGEX_ADVANCED is defined. If yes, features.h UNdefines wxHAS_REGEX_ADVANCED macro, and defines it, if no. The macro wxHAS_REGEX_ADVANCED, in turn, is used in regex.h to determine if among the enum constants wxRE_ADVANCED = 1 is present. The standard prebuilt Mageia 5 packages wxgtku3.0_0 and lib64wxgtku3.0-devel that I installed with the use of Mageia's software manager urpmi from Mageia repository WX_NO_REGEX_ADVANCED is defined, therefore wxHAS_REGEX_ADVANCED is undefined, and, hence, wxRE_ADVANCED is undefined either. Kicad 4.0.6 source package assumes wxRE_ADVANCED = 1, therefore the build process stops with the error.
Then I reverted /usr/include/wx-3.0/wx/regex.h and features.h to their original state and learned how to add the definition of wxRE_ADVANCED to CMakeLists.txt. However, I still have a question.
The recommended format of adding the definition to CMakeLists.txt I found at CMake command line for C++ #define is this:
if (NOT DEFINED wxRE_ADVANCED)
set(wxRE_ADVANCED 1)
endif()
add_definitions(-DwxRE_ADVANCED=$(wxRE_ADVANCED))
However, it did not work! The macro expansion for wxRE_ADVANCED in pcbnew/netlist_reader.cpp was empty. I printed it at compile time inserting the following lines into the netlist_reader.cpp file (this was hard to find, most of the recommended formats did not work. The correct one is in C preprocessor: expand macro in a #warning):
#define __STRINGIFY(TEXT) #TEXT
#define __WARNING(TEXT) __STRINGIFY(GCC warning TEXT)
#define WARNING(VALUE) __WARNING(__STRINGIFY(wxRE_ADVANCED = VALUE))
Pragma (WARNING(wxRE_ADVANCED))
Finally, I simplified the CMakeLists.txt definition down to this, and it was a success:
if (NOT DEFINED wxRE_ADVANCED)
set(wxRE_ADVANCED 1)
endif()
add_definitions(-DwxRE_ADVANCED=1)
My question: what is the meaning of "-DwxRE_ADVANCED=$(wxRE_ADVANCED)" if it does not work? Is it possible not to use set(wxRE_ADVANCED 1), and simply write add_definitions(-DwxRE_ADVANCED=1)? Thank you.
P.S. Yes, the Kicad 4.0.6 build process successfully finished with only one line added to the top level CMakeLists.txt file:
add_definitions(-DwxRE_ADVANCED=1)
A variable is called via $variable or ${variable}. Note the curly brackets, not parentheses.
Also, it is recommended to use:
target_compile_definitions(mytarget PUBLIC wxRE_ADVANCED=1)
on a target directly, rather than the general add_definitions() command.

How can I use cmake to test processes that are expected to fail with an exception? (e.g., failures due to clang's address sanitizer)

I've got some tests that test that clang's address sanitizer catch particular errors. (I want to ensure my understanding of the types of error it can catch is correct, and that future versions continue to catch the type of errors I'm expecting them to.) This means I have several tests that fail by crapping out with an OTHER_FAULT, which appears to be the fixed way that clang's runtime reports an error.
I've set the WILL_FAIL flag to TRUE for these tests, but this only seems to check the return value from a successful, exception-free failure. If the process terminates with an exception, cmake still classes it as a failure.
I've also tried using PASS_REGULAR_EXPRESSION to watch for the distinguishing messages that are printed out when this error occurs, but again, cmake seems to class the test as a failure if it terminates with an exception.
Is there anything I can do to get around this?
(clang-specific answers are also an option! - but I doubt this will be the last time I need to test something like this, so I'd prefer to know how to do it with cmake generally, if it's possible)
CTest provides only basic, commonly used interpretators for result of test programs. For implement other interpretators you can write simple program/script, which wraps the test and interpret its result as needed. E.g. C program (for Linux):
test_that_crash.c:
#include <unistd.h>
#include <stdlib.h>
#include <sys/types.h>
int main(int argc, char** argv)
{
pid_t pid = fork();
if(pid == -1)
{
// fork fails
return 1;
}
else if(pid)
{
// Parent - wait child and interpret its result
int status = 0;
wait(&status);
if(WIFSIGNALED(status)) return 0; // Signal-terminated means success
else return 1;
}
else
{
// Child - execute wrapped command
execvp(argv[1], argv + 1);
exit(1);
}
}
This program can be used in CMake as follows:
CMakeLists.txt:
# Compile our wrapper
add_executable(test_that_crash test_that_crash.c)
# Similar to add_test(name command), but test is assumed successfull only if it is crashed(signalled)
macro(add_test_crashed name command)
# Use generic flow of add_test() command for automatically recognize our executable target
add_test(NAME ${name} COMMAND test_that_crash ${command} ${ARGN})
endmacro(add_test_crashed)
# ...
# Add some test, which should crash
add_test_crashed(clang.crash.1 <clang-executable> <clang-args>)
There is also a clang-specific solution: configure its manner of exit using the ASAN_OPTIONS environment variable. (See https://github.com/google/sanitizers/wiki/AddressSanitizerFlags.) To do this, set the ASAN_OPTIONS environment variable to abort_on_error=0. When the address sanitizer detects a problem, the process will then do _exit(1) rather than (presumably) abort(), and will thus appear to have terminated cleanly. You can then pick this up using cmake's WILL_FAIL mechanism. (It's still not clear why OS X and Linux differ in this respect - but there you go.)
As a bonus, the test fails much more quickly.
(Another handy option that can improve turnaround time when running through cmake is to set ASAN_SYMBOLIZER_PATH to an empty value, which stops the address sanitizer symbolizing the stack traces. Symbolizing takes a moment, but there's no point doing it when running through cmake, since you can't see the output.)
Rather than do this by hand, I made a Python script that sets the environment appropriately on OS X (doing nothing on Linux), and invokes the test. I then add each asan test using a macro, along the lines of Tsyvarev's answer.
macro(add_asan_test basename)
add_executable(${basename} ${basename}.c)
add_test(NAME test/${basename} COMMAND ${CMAKE_CURRENT_SOURCE_DIR}/wrap_clang_sanitizer_test.py -a $<TARGET_FILE:${basename}>)
set_tests_properties(test/${basename} PROPERTIES WILL_FAIL TRUE)
endmacro()
This gives a simple pass/fail as quickly as possible. I'm in the habit of investigating failures by running the test in question from the shell by hand and examining the output, in which case I get the stack trace as normal (and the fact exiting by abort is a bit slow is less of a problem).
(There are similar options for the other sanitizers, but I haven't investigated them.)

Using value of __GLIBCXX__ in cmake

There are plenty of examples of using cmake to set a preprocessor value. I'm having the reverse problem -- I want to find the value of __GLIBCXX__ and then perform other cmake commands conditionally based on the result.
Up until now, I had been using the GCC version as a surrogate for libstdc++ functionality, like this:
if("${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU")
if (CMAKE_CXX_COMPILER_VERSION VERSION_LESS 4.6)
....
# other gcc versions
....
endif()
elseif ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang")
# and so on
endif()
The problem I'm now having is the fallout from a known issue with libstdc++ and gcc-4.8 c++11 regex support, and the fact on many setups clang reuses the system libstdc++, therefore inheriting the same problem. Under these circumstances, there's no version test for clang that will help, since it's specifically related to libstdc++, and my surrogate method of using the compiler version no longer works.
In order to fallback on Boost.Regex or PCRE if either clang or gcc are using the libstdc++ distributed with gcc-4.8 or earlier, the best way I can think of is to check if __GLIBCXX__ <= 20140404, but I can't see how to get cmake to do it in a straight-forward way, since clang might not always be using libstdc++, e.g. most OS X systems.
CheckVariableExists doesn't seem to help, I suppose for at least two reasons; firstly, a preprocessor macro isn't a variable, and secondly, it doesn't give the value, only indicates its presence.
You could use CHECK_CXX_SOURCE_COMPILES to compile a specific test which fails when your condition is not met:
INCLUDE (CheckCXXSourceCompiles)
CHECK_CXX_SOURCE_COMPILES(
"
#include <cstdio>
#ifdef __GLIBCXX__
#if __GLIBCXX__ <= 20140404
#error test failed
#endif
#endif
int main() { return 0;}
" GLIBCXX_TEST)
IF(NOT GLIBCXX_TEST)
MESSAGE(STATUS "__GLIBCXX__ test failed")
ENDIF()
Based on m.s.'s idea and taking Marc Glisse's observation about __GLIBCXX__ not being a reliable way to test for this, I wrote a CMake module to test for broken implementations of regex support. In order for this test to pass, the compiler will need to be targetting C++11 or higher.
Gist is here: https://gist.github.com/anonymous/7520ce6f64c63e2f8e79
Sample use:
include(CheckForRegex)
check_cxx_native_regex_works(USE_NATIVE_REGEX)
add_definitions("-DUSE_NATIVE_REGEX=${USE_NATIVE_REGEX}")
if (NOT USE_NATIVE_REGEX)
find_package(Boost REQUIRED COMPONENTS regex)
endif()

Is it possible to use #ifdef like checks in assembler?

I have tested a bit of assembler on Linux using the AT&T syntax. One thing that struck me was that the book I was reading was written from a 32-bit standpoint. Thus, all sizes would have to be changed to the correct 64-bit versions for me. Or I could (which I did) assemble the code using the --32 flag for as and the -melf_i386 flag for ld when linking. I have also adapted some of the code and to run on Windows under Cygwin.
But that got me thinking. Is there a way to do ifdef like checks in assembler to do one thing if I'm on Windows and another under Linux and also handle 32 vs 64 bit that way? For example to have a .globl _start under Linux and a .globl _main under Windows.
Or is this handled by checking before assembling and having different source files to assemble based on the result of the checks?
I.e. foo_linux.s and foo_windows.s
If so, how do you overcome that fact that you will not know which .s files you will use, and thus have to include, when you are creating your program?
For example, say that we have a socket_linux.s and a socket_windows.s. They both present an identical interface but do the OS specific work associated to sockets. But when I work with the sockets in my program I will not know if I need the Windows or Linux version included. So I would be kinda screwed :)
So how is this handled in Assembler? In C++ for example I could include my socket.h and socket.cpp and wrap all the Linux and Windows specific code in #ifdef statements.
If you use GCC to compile your files and name them .S (with uppercase S) or .sx, it will pass them through the preprocessor before invoking the assembler.
From the docs:
file.s
Assembler code.
file.S
file.sx
Assembler code which must be preprocessed.
You can add -v to the command line to see how the various sub-processes are invoked.
in MASM (.asm), you can use ifdef, ifndef and the likes, as:
ifdef X64
endif
When writing for different platforms you can define some macro for loading target specific files:
FILE target.h
#if defined(__arm__)
#define target "arm"
#elif defined(__x86_64__)
#if defined(_WIN64)
#define target "win64"
#else
#define target "linux64" // all non-Win share the same calling convention
#endif
#else
// 32bit defs
#endif
Then you can include target specific files with the macro, two string literals successively get one single literal:
#include "target.h"
#include "target_specific_code_" target ".h"
It includes one of these files:
target_specific_code_arm.h
target_specific_code_win64.h
target_specific_code_linux64.h
...
EDIT:
Like this, you can also define target specific assembler instructions for later use in inline assembly:
#ifdef ...
#define ASM_PP_LOAD_WORD "movi "
#else
#define ASM_PP_LOAD_WORD "mov "
#endif
or as macro
#ifdef ...
// when using intel assembler there is a different
// order of parameters
#define ASM_PP_LOAD_WORD(a, b) "movi " #b ", " #a
#else
#define ASM_PP_LOAD_WORD(a, b) "mov " #a ", " #b
#endif

MinGW and "declaration does not declare anything"

I'm working on converting a Linux project of mine to compile on Windows using MinGW. It compiles and runs just fine on Linux, but when I attempt to compile it with MinGW it bombs out with the following error message:
camera.h:11: error: declaration does not declare anything
camera.h:12: error: declaration does not declare anything
I'm kind of baffled why this is happening, because
I'm using the same version of g++ (4.4) on both Linux and Windows (via MinGW).
The contents of camera.h is absurdly simple.
Here's the code. It's choking on lines 11 and 12 where float near; and float far; are defined.
#include "Vector.h"
#ifndef _CAMERA_H_
#define _CAMERA_H_
class Camera{
public:
Vector eye;
Vector lookAt;
float fov;
float near;
float far;
};
#endif
Thanks for your help.
EDIT: Thanks both Dirk and mingos, that was exactly the problem!
Edit If you happen to include windef.h (either directly or indirectly), you will find
#define FAR
#define far
#define NEAR
#define near
there. I think, that this is the culprit.
Try
#undef near
#undef far
before your class definition.
Try giving them different names, like
float my_near;
float my_far;
I recall Borland using "near" and "far" as keywords (my 1992 Turbo C had these, back in MS-DOS era). Dunno if this is the case with gcc, but you can always try that.
In <windef.h>, you'll find on the following lines:
#define NEAR
#define near
Simple answer: you can't #undef them because they're a part of the Windows headers (_WINDEF_H will still be defined even if you #undef those definitions, so it won't be re-included if you try to #include <windef.h> again, not to mention the fact that if you #undef _WINDEF_H before using #include <windef.h> after your class definition, you'll end up with duplicate definitions for things like RECT, LONG, PROC and more), so the only other solution is to change your variable names.