I have a simple Chapel program to test the NetCDF module:
use NetCDF;
use NetCDF.C_NetCDF;
var f: int = ncopen("ppt2020_08_20.nc", NC_WRITE);
var status: int = nc_close(f);
and when I compile with:
chpl -I/usr/include -L/usr/lib/x86_64-linux-gnu -lnetcdf hello.chpl
it produces a list of errors about SysCTypes:
$CHPL_HOME/modules/packages/NetCDF.chpl:57: error: 'c_int' undeclared (first use this function)
$CHPL_HOME/modules/packages/NetCDF.chpl:77: error: 'c_char' undeclared (first use this function)
...
Would anyone see what my error is? I tried adding use SysCTypes; to my program, but that didn't seem to have an effect.
Sorry for the delayed response and for this bad behavior. This is a bug that's crept into the NetCDF module which seems not to have been caught by Chapel's nightly testing. To work around it, edit $CHPL_HOME/modules/packages/NetCDF.chpl, adding the line:
public use SysCTypes, SysBasic;
within the declaration of the C_NetCDF module (around line 50 in my copy of the sources). If you would consider filing this bug as an issue on the Chapel GitHub issue tracker, that would be great as well, though we'll try to get this fixed in the next release in any case.
With that change, your program almost compiles for me, except that nc_close() takes a c_int argument rather than a Chapel int. You could either lean on Chapel's type inference to cause this to happen:
var f = ncopen("ppt2020_08_20.nc", NC_WRITE);
or explicitly declare f to be of type c_int:
var f: c_int = ncopen("ppt2020_08_20.nc", NC_WRITE);
And then as one final note, I believe you should be able to drop the -lnetcdf from your chpl command-line as using the NetCDF module should cause this requirement to automatically be added.
Thanks for bringing this bug to our attention!
Related
I am very new to Frama-c and I got an issue when I am trying to open a C source file.
The error shows as
"fatal error: event.h: No such file or directory. Compilation terminated".
[kernel] Parsing FRAMAC_SHARE/libc/__fc_builtin_for_normalization.i (no preprocessing)
[kernel] Parsing WorkSpace/bipbuffer.c (with preprocessing)
[kernel] user error: failed to run: gcc -E -C -I. -dD -D__FRAMAC__ -nostdinc -D__FC_MACHDEP_X86_32 -I/usr/share/frama-c/libc -o '/tmp/bipbuffer.ce6d077.i' '/home/xxx/WorkSpace/bipbuffer.c' you may set the CPP environment variable to select the proper preprocessor command or use the option "-cpp-command".
[kernel] user error: stopping on file "/home/xxx/WorkSpace/bipbuffer.c" that has errors. Add'-kernel-msg-key pp' for preprocessing command.
So bascially I am trying to open a C source file but it returns an error like this. I aslo tried other very simple C files like hello world and other slicing functions, it works well.
I thought it was because I didn't have the dependencies of 'event.h' but it still return these errors after I installed the libevent dependencies. I am not sure if I need to manually set some path of the dependencies for frama-c
Here is part of the C file (Source link: https://memcached.org/) that I would like to open:
#include "stdio.h"
#include <stdlib.h>
/* for memcpy */
#include <string.h>
#include "bipbuffer.h"
static size_t bipbuf_sizeof(const unsigned int size)
{
return sizeof(bipbuf_t) + size;
}
int bipbuf_unused(const bipbuf_t* me)
{
if (1 == me->b_inuse)
/* distance between region B and region A */
return me->a_start - me->b_end;
else
return me->size - me->a_end;
}
......
Thanks,
Compilers and other tools working with C source code need to know where to find header files. There are some standard places where they look automatically, but Frama-C has fewer of those than (and different ones from) a normal compiler.
You need to find out where event.h is installed, then pass something like -cpp-extra-args "-I /path/to/directory/" to Frama-C. Pass the directory name only, not including the name event.h itself.
In addition to Isabelle Newbie's answer, I'd like to point out that the Chlorine version of Frama-C, whose beta has been recently announced, features a new option -json-compilation-database that attempts to read the arguments to be passed to the pre-processor from a compilation database.
Such database can be generated directly by cmake, but there are solutions for make-based project such as the one you refer to, in particular bear, which intercepts the commands launched by make to build the database.
Here's a detailed summary of how you could proceed, using the new -json-compilation-database option from Frama-C 17 Chlorine, plus an extra script list_files.py (which is not in the beta, but will be available in the final 17 release, and can be downloaded here):
Get the source files you want to analyze with Frama-C, run ./configure, and if possible try to disable optional dependencies from external libraries; for instance, some code bases include optional dependencies based on availability of libraries/system features, but have fallback options (resorting to standard C library or POSIX functions). The more you give Frama-C, the better the chances of analyzing it well, so if such external libraries are not essential, excluding them might help get a more "POSIXy" code, which should help. This is typically visible in config.h files, in macros commonly named HAVE_*.
Compile and install Build EAR or some equivalent tool to obtain a compile_commands.json file.
Run bear make (or cmake with flag CMAKE_EXPORT_COMPILE_COMMANDS) to get the compile_commands.json file.
Run the aforementioned list_files.py in the directory containing compile_commands.json to obtain the list of C sources used during compilation.
Run Frama-C (17 Chlorine or newer), giving it the list of sources found in the previous step, plus option -json-compilation-database . to parse the compile_commands.json and, hopefully, get the appropriate preprocessing flags.
Ideally, this should suffice, but in practice, this is rarely enough. In particular due to the presence of external libraries and non-C99, non-POSIX functions, the following steps are always needed.
6. Inclusion of external libraries
At this step, Frama-C will complain about the lack of event.h. You'll have to include the headers of this library yourself. Note: copying headers directly from your /usr/include is not likely to work, due to several architecture-specific definitions, especially files such as bits/*.h..
Instead, consider downloading the external libraries and preparing them (e.g. running ./configure at least). Then manually add the extra include directory via -cpp-extra-args="-I <path/to/your/sources/for/libevent.h>/include".
7. Inclusion of missing non-POSIX headers
Some other headers may be missing, in particular GNU- or BSD-specific sources (e.g. sysexits.h). Get these headers and add them when necessary. The error message in this case comes from the preprocessor (gcc) and is similar to this:
memcached.c:51:10: fatal error: sysexits.h: No such file or directory
#include <sysexits.h>
^~~~~~~~~~~~
compilation terminated.
8. Definition of missing non-POSIX types and constants
At this point, all necessary headers should be available, but parsing with Frama-C may still fail. This is due to usage of non-POSIX type definitions (e.g. caddr_t, struct ling), non-POSIX constants (e.g. MAXPATHLEN, SOCK_NONBLOCK, NI_MAXSERV). Error messages typically resemble the following:
[kernel] memcached.c:3261: Failure: Cannot resolve variable MAXPATHLEN
Constants are often easy to provide manually, by grepping what's available in your /usr/include.
Type definitions, on the other hand, may require some copy-pasting at the right places, especially if they depend on other types which are also missing. This step is hardly automatizable, but relatively straightforward once you get used to some specific error messages.
For instance, the following error message is related to a missing type definition (caddr_t):
[kernel] Parsing memcached.c (with preprocessing)
[kernel] memcached.c:1074:
syntax error:
Location: line 1074, between columns 38 and 47, before or at token: c
1072 *hdr++ = 0;
1073 *hdr++ = 0;
1074 assert((void *) hdr == (caddr_t)c->msglist[i].msg_iov[0].iov_base + UDP_HEADER_SIZE);
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
1075 }
1076
Note that the token just before c is (caddr_t), which has never been defined (it is often defined as either void * or char *).
The following error message is related to an incomplete type, i.e., a struct used somewhere but never defined:
[kernel] memcached.c:5811: User Error:
variable `ling' has initializer but incomplete type
It means that variable ling's type, which is struct linger (non-POSIX), has never been defined. In this case, we can copy it from our /usr/include/bits/socket.h:
struct linger
{
int l_onoff; /* Nonzero to linger on close. */
int l_linger; /* Time to linger. */
};
Note: if there are POSIX constants/definitions missing from Frama-C's libc, consider notifying its developers, or proposing pull requests in Frama-C's Github.
9. Fixing incompatible and missing function prototypes
Parsing is likely to succeed after the previous step, but it may still fail due to incompatible function prototypes. For instance, you may get:
[kernel] User Error: Incompatible declaration for usleep:
different integer types int and unsigned int
First declaration was at assoc.c:238
Current declaration is at items.c:1573
This is the consequence of a warning emitted earlier:
[kernel:typing:implicit-function-declaration] slabs.c:1150: Warning:
Calling undeclared function usleep. Old style K&R code?
It means that function usleep is called, but it does not have a prototype, therefore Frama-C uses the pre-C99 convention of "implicit int": it generates such a prototype, but later in the code, an actual declaration of usleep is found, and its type is not int. Hence the error.
To prevent this, you need to ensure usleep's prototype is properly included. Since it is not POSIX.1-2008, you need to either define/undefine the appropriate macros (see unistd.h), or add your own prototype.
At the end, this should allow Frama-C to parse the files and build an AST.
However, there are several missing prototypes yet; we were just lucky that none conflicted with actual declarations. Ideally, you'll consider the parsing stage done when there are no more messages such as implicit-function-declaration and similar warnings.
Some of the missing prototypes in memcached, such as getsubopt, are POSIX and should be integrated into Frama-C's standard library. Others might make part of a small library of non-standard stubs, to be reused for other software.
Contributing with results for future reuse
Successful conclusion of the parsing stage for such open source libraries is enough to consider them for integration into this repository of open source case studies, so that future users can start their analyses without having to redo all of these steps. (The repository is oriented towards Eva, but not exclusively: parsing is useful for all of Frama-C plug-ins.)
I'm getting this on the console in a QML app:
QFont::setPointSizeF: Point size <= 0 (0.000000), must be greater than 0
The app is not crashing so I can't use the debugger to get a backtrace for the exception. How do I see where the error originates from?
If you know the function the warning occurs in (in this case, QFont::setPointSizeF()), you can put a breakpoint there. Following the stack trace will lead you to the code that calls that function.
If the warning doesn't include the name of the function and you have the source code available, use git grep with part of the warning to get an idea of where it comes from. This approach can be a bit of trial and error, as the code may span more than one line, etc, and so you might have to try different parts of the string.
If the warning doesn't include the name of the function, you don't have the source code available and/or you don't like the previous approach, use the QT_MESSAGE_PATTERN environment variable:
QT_MESSAGE_PATTERN="%{function}: %{message}"
For the full list of variables at your disposal, see the qSetMessagePattern() docs:
%{appname} - QCoreApplication::applicationName()
%{category} - Logging category
%{file} - Path to source file
%{function} - Function
%{line} - Line in source file
%{message} - The actual message
%{pid} - QCoreApplication::applicationPid()
%{threadid} - The system-wide ID of current thread (if it can be obtained)
%{qthreadptr} - A pointer to the current QThread (result of QThread::currentThread())
%{type} - "debug", "warning", "critical" or "fatal"
%{time process} - time of the message, in seconds since the process started (the token "process" is literal)
%{time boot} - the time of the message, in seconds since the system boot if that can be determined (the token "boot" is literal). If the time since boot could not be obtained, the output is indeterminate (see QElapsedTimer::msecsSinceReference()).
%{time [format]} - system time when the message occurred, formatted by passing the format to QDateTime::toString(). If the format is not specified, the format of Qt::ISODate is used.
%{backtrace [depth=N] [separator="..."]} - A backtrace with the number of frames specified by the optional depth parameter (defaults to 5), and separated by the optional separator parameter (defaults to "|"). This expansion is available only on some platforms (currently only platfoms using glibc). Names are only known for exported functions. If you want to see the name of every function in your application, use QMAKE_LFLAGS += -rdynamic. When reading backtraces, take into account that frames might be missing due to inlining or tail call optimization.
On an unrelated note, the %{time [format]} placeholder is quite useful to quickly "profile" code by qDebug()ing before and after it.
I think you can use qInstallMessageHandler (Qt5) or qInstallMsgHandler (Qt4) to specify a callback which will intercept all qDebug() / qInfo() / etc. messages (example code is in the link). Then you can just add a breakpoint in this callback function and get a nice callstack.
Aside from the obvious, searching your code for calls to setPointSize[F], you can try the following depending on your environment (which you didn't disclose):
If you have the debugging symbols of the Qt libs installed and are using a decent debugger, you can set a conditional breakpoint on the first line in QFont::setPointSizeF() with the condition set to pointSize <= 0. Even if conditional breakpoints don't work you should still be able to set one and step through every call until you've found the culprit.
On Linux there's the tool ltrace which displays all calls of a binary into shared libs, and I suppose there's something similar in the M$ VS toolbox. You can grep the output for calls to setPointSize directly, but of course this won't work for calls within the lib itself (which I guess could be the case when it handles the QML internally).
I want to use R's mathematical functions as provided in libRmath from Ocaml. I successfully installed the library via brew tap homebrew science && brew install --with-librmath-only r. I end up with a .dylib in /usr/local/lib and a .h in /usr/local/include. Following the Ocaml ctypes tutorial, i do this in utop
#require "ctypes.foreign";;
open Ctypes;;
open Foreign;;
let test_pow = foreign "pow_di" (float #-> int #-> returning float);;
this complains that it can't find the symbol. What am I doing wrong? Do I need to open the dynamic library first? Set some environment variables? After googling, I also did this:
nm -gU /usr/local/lib/libRmath.dylib
which gives a bunch of symbols all with a leading underscore including 00000000000013ff T _R_pow_di. In the header file, pow_di is defined via some #define directive from _R_pow_di. I did try variations of the name like "R_pow_di" etc.
Edit: I tried compiling a simple C program using Rmath using Xcode. After setting the include path manually to include /usr/local/include, Xcode can find the header file Rmath.h. However, inside the header file, there is an include of R_ext/Boolean.h which does not seem to exist. This error is flagged by Xcode and compilation stops.
Noob alert: this may be totally obvious to a C programmer...
In order to use external library you still need to link. There're at least two different ways, either link using compiler, or link even more dynamically using dlopen.
For the first method use the following command (as an initial approximation):
ocamlbuild -pkg ctypes.foreign -lflags -cclib,-lRmath yourapp.native
under premise that your code is put into yourapp.ml file.
The second method is to use ctypes interface to dlopen to open the library. Using the correct types and name for the C function call, this goes like this:
let library = Dl.dlopen ~filename:"libRmath.dylib" ~flags:[]
let test_pow = foreign ~from:library "R_pow_di" (double #-> int #-> returning double)
I'm trying to get started with OpenCL but came across weird behavior of the OpenCL compiler with respect to white-space and can't seem to find any documentation about that.
C-style single-line comments (// foo) immediately cause a meaningless build error: At end of source: error: expected a "}". Multi-line comments (/* bar */) seem to work fine.
Line breaks seem to get stripped without adding whitespace which can cause errors. This example will not compile because of that:
__kernel
void TestKernel() {}
line 1: error: identifier "__kernelvoid" is undefined
This may totally depend on my machine and/or configuration but can somebody confirm that these things should not be this way?
I am using OpenCL via Cloo from .net/C#. The driver is from AMD OpenCL 2.0 AMD-APP (1642.5)
I think I figured it out. I was doing this:
var program = new ComputeProgram(context, File.ReadAllLines(filename));
File.ReadAllLines() returns an array of strings without the line-break characters which is the root of the errors I was getting.
Using File.ReadAllTest() instead fixed all the problems:
var program = new ComputeProgram(context, File.ReadAllText(filename));
But in my opinion some of the blame goes to either Cloo or the OpenCL API for accepting a string array but just concatenating it together..
I have the weird problem that when I include anything from the QtNetwork module into my Qt Desktop application, I get a bunch of errors, before anything of the included is even used.
For example, if I include QtNetwork/QHostAddress, I get the following errors:
..\..\QtSDK\Desktop\Qt\4.8.1\mingw\include/QtNetwork/qabstractsocket.h:66: error: template with C linkage
..\..\QtSDK\Desktop\Qt\4.8.1\mingw\include/QtNetwork/qabstractsocket.h:253: error: declaration of C function 'QDebug operator<<(QDebug, QAbstractSocket::SocketState)' conflicts with
..\..\QtSDK\Desktop\Qt\4.8.1\mingw\include/QtNetwork/qabstractsocket.h:252: error: previous declaration 'QDebug operator<<(QDebug, QAbstractSocket::SocketError)' here
..\..\QtSDK\Desktop\Qt\4.8.1\mingw\include/QtNetwork/qhostaddress.h:141: error: declaration of C function 'QDebug operator<<(QDebug, const QHostAddress&)' conflicts with
..\..\QtSDK\Desktop\Qt\4.8.1\mingw\include/QtNetwork/qabstractsocket.h:253: error: previous declaration 'QDebug operator<<(QDebug, QAbstractSocket::SocketState)' here
..\..\QtSDK\Desktop\Qt\4.8.1\mingw\include/QtNetwork/qhostaddress.h:148: error: declaration of C function 'QDataStream& operator<<(QDataStream&, const QHostAddress&)' conflicts with
..\..\QtSDK\Desktop\Qt\4.8.1\mingw\include/QtNetwork/qhostaddress.h:141: error: previous declaration 'QDebug operator<<(QDebug, const QHostAddress&)' here
Of course, I added the line
Qt += network
to my .pro file, so this can't be the issue. Another module (opengl) could be included without problems.
I already ensured that nothing is wrong with my Qt installation itself by creating a dummy project which did nothing but including QtNetwork. It worked just fine.
So, there must be something wrong with my project, but as the error messages only occur in this special case I have no idea what information to provide for you.
All I can say is that the program was pure C-Code before and it is now being changed to C++ with Qt, so there is still a mix in it. But this does not seem to be a problem as long as QtNetwork is not included.
Any ideas on how to solve this or on what information is relevant for this problem?
I finally figured out my problem. The solution is quite easy:
I included QTNetwork into a header file, which in turn was included into some other .cpp-file by my team member, but he wrongly placed the include-statement in an extern "C" block, so that in the end QTNetwork was included as an extern "C" even though it is C++.
So, two lessons learned:
Don't rely on the correctness of your team mates' code.
If an include leads to errors, follow up the whole include chain to track down the problem.