I am trying to create a small set of filepath functions that I intend to compile across linux and windows (I prefer not to use a big library). I want to have a global constant PATH_SEPARATOR that depends on the OS environment. This is what I set at the top of header file.
Code:
#include <stdio.h>
const char PATH_SEPARATOR =
#ifdef _WIN32
'';
#else
'/';
#endif I was hoping to test this while compiling this in a linux environment using gcc, thusly:
Code:
int main (int argc, char const* argv[])
}
[code]....
where apparently, I seem not to be able to "set" a part of the code to have "_WIN32" defined. I don't know if I explained this clearly.
Say I have two projects A and B. A depends on B. If project A defines a macro to be 100 and project B defines the same macro to be 200. In project A, if I use this macro, what value would this macro be? Let's just forget macro is evil for the time being. Let's also forget that it is not good to define the same macro twice for the time being.
Is it possible to define a macro with in a macro? Any trick will do. I am trying to do quick conversion of cuda program to open mp by defining some macros at the top:
I'm doing right now is creating a function that callocs (I prefer this to malloc) and returns a string, and it will work similar to printf, I'm calling the function alloCpy(),I have several values that I need in a malloced string, so I call Code: myAllocedString = alloCpy("Value 1 is %s, value 2 is %s, and value 3 is %d", str1, str2, num); To do this I'm using the Variadic Macro, the reason I'm not just using a Variadic Function such as this: Code: char* alloCpy(char *format, ...) {} is because I need to append NULL to the end for the sake of looping through arguments, and I'm understanding it thusfar, but I have a few issues, first of all, I tried defining the Macro in a header file, but when I try to call it I get the error "Undefined reference to alloCpy". Also, to loop through arguments to get string lengths I'm using va_arg(args, char*) which requires all the arguments to be of type char*. Here is my code: myheader.h:
So, how can I do this to, first of all, make my macro function accessible from other files importing myheader.h, and second, how can I make it accept any type of argument like printf, so that my example above would work?
Code: #define FOO BAR #if FOO == BAR doX(); #else doY(); #endif
This causes doX(); to be executed. But the intent is to have doY(); be run. I'm guessing this is because BAR is undefined and therefore blank, so blank equals blank. Is there some way to compare the symbol FOO was set to instead of its value, BAR?
"If you examine the expansion of max, you will notice some pitfalls. The expressions are evaluated twice; this is bad if they involve side effects like increment operators or input and output. For instance, the below example will increment the larger twice."
#define max(A, B) ((A) > (B) ? (A) : (B))
max(i++, j++)/* WRONG */
I don't see what the problem is with the code above. i is incremented and j is incremented and then it performs a ternary operation to see which is greater. Am I missing something?
I'm trying to define a 7x5 array in main and then use it in a different function that will fill that array with random floats between 0.0 and 1.0 and then use main to print the final, filled array.
if ( creal(phi[i]) < 0.0 ) i_phi [i] = 0.0; if ( creal(phi[i]) > 1.0) i_phi [i] = 1.0; }
[Code]....
Printed numbers are showing a lot of fluctuation around limits eg, 1.00542, 1.0002 and -2.45829e-12.
I really have no idea why the limits are not applied for a lot of cells but my guess is that it's a problem from the CREAL function. Also I've changed the CREAL with __REAL__ but still the same problem shows up.
I need writing a macro that would return true/false (1/0) )value. I want to check if a certain element exists in the array. The macro will accept array, its size, and the value to be compared, and must return yes or no. Here is the code that I have written:
Code: #define EXISTS(T, a, n, val) do { char ret=0; T *a_ = (a); size_t n_ = (n); for (; n_ > 0; --n_, ++a_){ ret = (*a_ == val); } } while(0)
i would like to know if its possible to use a c# command to attach a macro ( JitBix MacroRecorder ) so it would send keystrokes while the process/program was minimized. i've tried with [lapeiro, on 20 January 2014 - 06:43 AM, said: i would like to know if its possible to use a c# command to attach a macro ( JitBix MacroRecorder ) so it would send keystrokes while the process/program was minimized.
#define ALLOCSIZE 10000 /* size of available space */ static char allocbuf[ALLOCSIZE]; /* storage for alloc */ static char *allocp = allocbuf; /* next free position */ char *alloc(int n) /* return pointer to n characters */
[Code] ....
The logic here I don't understand:
if (allocbuf + ALLOCSIZE - allocp >= n)
allocbuf is a char array allocated with 10000 positions. We add that to ALLOCSIZE macro which is 10000. Does that return a value of 20000? If so, it doesn't make sense to do this because all we had to do was this:
if (allocbuf - allocp >= n)
That takes length of allocbuf which is 10000 and subtracts allocp from it. So if allocp is 1000 we are left with 9000 available slots. And we can use that to check if we have enough to allocate n elements.
I'm trying to build libglib using MSVC. libglib doesn't use dllexport - so to create usable DLLs it needs to generate a .DEF file. It does this by using a .symbols file. Here's a cut-down example:-
Code: /* This file lists all exported symbols. It is used to generate the glib.def file used to control exports on Windows.*/
/* glib.symbols */ g_mkdir_with_parents
#ifdef G_OS_WIN32 g_file_get_contents_utf8 #endif
The following commands would produce the following files called glib.def
Problem:- Although I can run the macro as a pre-build step (and it does produce conditional entries in the generated .DEF file) it DOESN'T produce the word EXPORTS at the top of the file. So the linker then fails to recognise it as a valid .DEF file.
How can I add that word EXPORTS to the top of the generated file? I tried just adding EXPORTS to the top of the symbols file but that didn't work. I also tried this variation on the macro:-
Code: #define DEBUG_NEW new(__FILE__, __LINE__) #define new DEBUG_NEW
and overloading operator new for debugging purposes. It usually works but there is a problem when use operator new syntax in code instead of directly use new. I can change my code but i can't change third party's code. Something like this:
In the following example, SET_DARKENING_PARAMETERS_0 is a fairly simple macro which accepts 9 parameters. The first one is called driver and the other 8 are all ints. Basically, the 8 x ints get assigned to the first 8 elements of an array which is owned by driver. I can call the macro successfully if I do this:-
But the two combined macros won't compile with VC8. Basically, I get warning #C4003 (not enough parameters for macro 'SET_DARKENING_PARAMETERS_0') followed by a load of syntax errors. However, the code (allegedly) compiles with gcc.
I'm wondering if macro CONFIG_OPTION_DARKENING_PARAMETERS might be getting truncated to just 500, (with the following parameters getting ignored)?
I am looking at functions still and can't see the point in declaring the function at the top of the program, and then defining later i.e.
Code: #include <iostream> int add (int x, int y) { return x + y;
[Code] .....
I obviously don't have much real world experience with this and am interested to see where declaring and defining later would be useful and/or beneficial.
I am work on building a simple parse tree and the layout of my code look like this:
Headers pt_node.hiterator.hparsetree.h
Source files node.cppparsetree.cppmain.cpp
I am still relatively new to C++ , and have been advised to include function definition for the member function of both pt_node class and iterator class in the node.cpp file
I particular I have declare the following iterator.h:
Programe #1 // file.h class File { public: static const int var = 9; };
[Code]....
Program#1 is running fine, but program#2 gives linker error:
error LNK2005: "int GlobalVar" (?x@@3HA) already defined in file.obj
I know the header files are never compiled. Then in the above case, how the compiler knows the definition of variable var, but not able to find the definition of GlobalVar? What is the difference between this two programs?
