Hi I want to improve my math library,
when I compute lenght of something I do
assert( !equal(len,0.0));
const f32 invsqrt = 1.0/sqrt(len);
X*= invsqrt;
Y*= invsqrt;
Z*= invsqrt;
this code is nice and if I do wrongly the division by zero the code breaks
"Runtime has requested to break application at line .. Vector.h line 88"
This is nice, but I want to do better, I want to show where error is REALLY.
So instead of showing "vector.h" and line 88 I want to show "main.cpp" "line 15" (if the getLength function is called at line 15 in main).
Vector is header only, so I think that achieving that is possible (that's just a feeling).. but how?
Thanks in advance. I hope you can see how usefull would be doing that.
That's where the code is, so that where it will break.
I think what you mean is to see the call stack.
In visual studio it's at: Debug -> Windows -> Call Stack.
The call stack can show you how you got to that line of code (which function were called in the work flow)
Related
I'm searching for a tool to get the used header (if there is one/more) for every line/statment in my c++ code.
Example:
#include<iostream>
std::cout << "hallo";
The output i'd like to see:
line 2: std::cout uses "iostream"
I found this question, the tools there do most of the part, they show dependency per file.
Does anyone know such a tool or how to acomplish this with the tools given in the answers in the question above?
Goal: I'm checking code for the conformity to a standard which i have a list of allowed headers for. With the desired output I can create a metric saying something like: 60% of the code is using allowed headers, 15% is using other headers or something like that.
This is not completely what you want but you can use Eclipse CDT to know where std::cout is declared.
If you press F3 when cout is selected in Eclipse, you will jump to this line of code inside iostream header file on the system with gcc 7:
extern ostream cout; /// Linked to standard output
You can try CppDepend to get all the methods called by a specific one with the location of each method called.
I am facing issues with memory allocation in Scilab after compiling.
I am compiling on a Red Hat on ppc64 (POWER8). Stack limits are already set to unlimited (ulimit -s unlimited). The ./configure script (with several options I am not showing here) runs successfully, but the make all fails and stops. When it stops, it is stuck at the Scilab command prompt with this message:
./bin/scilab-cli -ns -noatomsautoload -f modules/functions/scripts/buildmacros/buildmacros.sce
stacksize(5000000);
!--error 10001
stacksize: Cannot allocate memory.
%s: Cannot allocate this quantity of memory.
at line 27 of exec file called by :
exec('modules/functions/scripts/buildmacros/buildmacros.sce',-1)
-->
I have investigated a bit, and that error message seems to be called of course at line 00027 in buildmatros.sce, where the function stacksize(5000000) is called.
This function is defined in:
scilab-5.5.1/modules/core/sci_gateway/c/sci_stacksize.c
I found a version of the file at this page: http://doxygen.scilab.org/master_wg/d5/dfb/sci__stacksize_8c_source.html.
The condition that is FALSE and that triggers the message seems to me to show up at line 00295.
Inside that file, you see that error is displayed whenever the stacksize given as input is LARGER than what is returned by the method get_max_memory_for_scilab_stack() from the class:
scilab-5.5.1/modules/core/src/c/stackinfo.c
Again I found a version online at the following page:
http://doxygen.scilab.org/master_wg/dd/dfb/stackinfo_8h.html#afbd65a57df45bed9445a7393a4558395
The Method is declared from line 109.
It seems to invoke a variable called MAXLONG, which is however NEVER explicitly declared! As you see, it is declared several times (line 00019, 00035, 00043, 00050), but all lines are commented! [correction: the lines are NOT commented, it was my false understanding of # being a comment sign, but it's not]
So my guess is: MAXLONG is not declared, so the function does not return a value (or it returns 0) and therefore the error message is triggered because the stacksize given as input is higher than 0 or NULL or N/A.
My questions are then:
Why are all lines commented where MAXLONG is defined?
Where does MAXLONG originate from? Is it something passed from the kernel?
How can I solve the problem?
Thanks!
PS - I tried to uncomment the line in buildmacros, and it compiled and installed without issues. However, when I started scilab-cli, it displayed the same message again.
Edit after further investigation:
After further investigation, I found out that what I thought were the comments are indeed instructions for the compiler... but I kept those errors of mine, so that the answer to my question is understandable.
Here are my new points.
In Scilab I noticed that by giving an input stacksize out of bounds, the same method get_max_memory_for_scilab_stack() is invoked, to get the upper bound. The lower bound I've seen it's defined by default.
-->stacksize(1)
!--error 1504
stacksize: Out of bounds value. Not in [180000,268435454].
Also the stacksize used seems fine:
-->stacksize()
ans =
7999994. 332.
However, when trying to give such value an input inbetween, it fails.
-->stacksize(1)
!--error 1504
stacksize: Out of bounds value. Not in [180000,268435454].
It seems to invoke a variable called MAXLONG
It's not a variable, but a pre-processor macro.
Why are all lines commented where MAXLONG is defined?
You should ask that from the person who commented the lines. They're not commented in scilab-5.5.1 that's online.
Where does MAXLONG originate from? Is it something passed from the kernel?
It's defined in the file scilab-5.5.1/modules/core/src/c/stackinfo.c. It's defined to the same value as LONG_MAX which is defined by the standard c library (<limits.h> header). If the macro is not supplied by the standard library, then it's defined to some other, platform specific value.
How can I solve the problem?
If your problem originates from the lack of definition for MAXLONG, then you must define it. One way going about it is to uncomment the lines that define it. Or re-download the original sources since yours don't appear to match with the official ones.
This is a problem on spoj.com (http://www.spoj.com/problems/PRIC/) .We have to check whether numbers of the sequence : ai=( a(i-1)+1234567890 ) mod 2^31 are prime or not, 1st number is 1.
My code is given below (Please try to ignore the clumsiness.) based on sieve of eratosthenes .
The PROBLEM : We have to print "prime(1) or not(0)" for sequence upto i=33,333,333 , My code works perfectly fine for i( c3 in the code) values upto 8000 or so and after that (e.g c3>19000 ) it starts giving The SIGFPE error . Now i googled about the error , it has something to do with division/ mod by 0. But why is it that code works for c3 values upto 9000 but not beyond that?
Depending on your compiler and development environment, you should read up on the concept of a Debugger. This answer has a guide to use gdb. If you are using Visual Studio, Code::Blocks or any other IDE, look up the debugging features. For instance how to set a breakpoint or step into/out of/over a function call for instance, watching or changing variables etc. (I'm mentioning these things to give you vital hints for Google search-words, wink wink nudge nudge).
EDIT:
Copy-pasted the code and saved it, compiled with gcc -g for debug symbols and -lm to link the math library, I ran it through gdb and it gave me this output:
Program received signal SIGFPE, Arithmetic exception.
0x0000000000400707 in sieve (prime=0x6626a0) at t.c:43
43 if (a%prime2[j]==0){
This tells you to look at line 43, at the if statement that uses a modulo operation. This seems to be the place you are doing the modulo zero.
Do note that line 43 in the document I got when I copy-pasted your code from Stackoverflow, may not be line 43 in your document.
EDIT2:
Hey my answer was unaccepted! - why was that :) ?
At the moment I'm using an eclipse-like IDE and the corresponding debug perspective, that most of you are probably familiar with. While debugging code I quite often find myself stepping through many lines of code and observing variables and double checking if everything is as it is supposed to be.
But suppose there is something like this:
1. important line, e.g. generating a new object;
2. another important line, e.g. some tricky class method;
3. for (int i = 0; i < some_limit; ++i)
4. some_array[i]++;
5. more important stuff;
Obviously I'm interested in what happens in lines 1,2 and 5 (I know this is a poor example, but please bear with me for a little while longer) but I don't want to step through all hundreds (or even thousands) of iterations of lines 3/4.
So, finally, my question: Is there some way to step directly over the for-cycle? What I do right now is set a new breakpoint at line 5 and let the program run as soon as I hit line 3 and I believe this is not an optimal solution.
edit: The eclipse implementation of what ks1322 proposed is called "Run to line" and is mapped to ctrl-r
Use until command instead of next.
From gdb documentation:
Continue running until a source line past the current line, in the
current stack frame, is reached. This command is used to avoid single
stepping through a loop more than once.
If you will use until instead of next, gdb will step over loops only once, which almost exactly what you want.
I'm looking for a good, fully featured C++ assert macro for VisualStudio. With features like be able to ignore an assert once or always, to be able to break exactly where the macro gets called (and not inside macro code), and getting a stack trace.
Before I have to hunker down and write one, I figured I'd ask if anyone knows about any available ones out there.
Any suggestions?
Thanks!
See Charles Nicholson's blog for a good discussion of an assert macro. His solution breaks the debugger at the faulting line of code (and not inside the failed assertion handler), and he also solves the problem of not getting warnings about unused variables when assertions are disabled without incurring any runtime costs.
Here's a link to an article I wrote for DDJ that described, among other things, a library that does much of what you're looking for. Although I don't just use macros, I also implement functions in a DLL.
http://www.ddj.com/architect/184406106
The article from a few years ago and, although I have made many additions, I still use it very liberally in my everyday code.
_ASSERTE breaks exactly where you want it - but does not meet your other criteria.
_ASSERTE is nice because it displays the actual assertion text along with the filename and line number. This means you can do this:
_ASSERTE(bufLen > 0 && "bufLen needs to be greater than 0");
OpenOffice has some assertion code that has an option of logging to a message box. Probably not exactly what you want, but instructive maybe?
I released PPK_ASSERT. While it doesn't open a dialog box, on Windows the default handler opens a console where you get to read the assertion message and get to decide which action to take.
#include <pempek_assert.h>
int main()
{
float min = 0.0f;
float max = 1.0f;
float v = 2.0f;
PPK_ASSERT(v > min && v < max, "invalid value: %f, must be between %f and %f", v, min, max);
return 0;
}