I get byte redefinition error when I try to compile my application. One is defined in Crypto++ library and the other one in rpcdnr.h of Windows Kit. I tried many things but none worked. Any idea to solve the problem is appreciated.
typedef unsigned char byte;
Thanks
P.S. I'm using Qt on Windows.
Namespaces were created for this reason so to avoid interference between identifiers define them under a namspace:
namespace crypto{
typedef unsigned char byte;
};
namespace rpcndr{
typedef unsigned char byte;
};
int main(){
crypto::byte bValue = 7;
rpcndr::byte bvalue2 = 10;
ret
}
Related
I want to use qint16_be, quint16_be, quint32_be etc. as a data type for big endian
what I am trying is something like this
#include <QtEndian>
typedef quint16_be uint16_t;
And I am getting error
C:/Qt/5.15.2/mingw81_64/include/QtCore/qendian.h:429:28: error: conflicting declaration 'typedef QBEInteger<short int> qint16_be'
typedef QBEInteger<qint16> qint16_be;
C:/Qt/Tools/mingw810_64/x86_64-w64-mingw32/include/stdint.h:38:25: note: previous declaration as 'typedef short unsigned int qint16_be'
typedef unsigned short qint16_be;
I have not included stdint.h in my project.
Any idea how would I resolve it
Here we go: an MCVE for qToBigEndian():
#include <QtCore>
int main()
{
const uint16_t sample = 0x0201;
QByteArray data((const char*)&sample, sizeof sample);
qDebug() << data;
const uint16_t sampleBE = qToBigEndian(sample);
QByteArray dataBE((const char*)&sampleBE, sizeof sampleBE);
qDebug() << dataBE;
}
Output:
"\x01\x02"
"\x02\x01"
I ran this sample in VS2019 on my Intel laptop which has little-endian architecture.
Respectively, the byte order was changed due to the call of qToBigEndian().
The conversion to QByteArray was a quick hack.
Nevertheless, conversion of const uint16_t* to const char* is allowed (with the intention to get access to the byte representation of something).
memcpy() is another permitted way to achieve this.
There is a .dll and .lib file for the evaluation board AD5501 after installing its drivers. It contains the functions to use to connect to the board and send instructions to it.
A quick search in analog's website (https://ez.analog.com/thread/11121) revealed a document that contains the commands in the above mentioned DLL file. And it is mentioned that the DLL is written in C++. At the end of the page there is a pdf containing VB6 function declarations of the DLL.
I have no knowledge of VB6 but the fact that the DLL has been written in C++ led me to assume that I should be able to access the function in the DLL or LIB file if i know the function prototype in a C++ program. Is this a correct assumption?
And the website has description of the function prototype. So i made a test C++ program as given below :
#include <iostream>
using namespace std;
unsigned int Search_For_Boards (unsigned int VID, unsigned int PID, unsigned int *Num_boards, char *PartPath[]);
int Connect(unsigned int VID, unsigned int PID, char PartPath, unsigned int *Handle);
int Download_Firmware(unsigned int Handle, char pcFilePath[]);
int Vendor_Request(unsigned int Handle, unsigned char Request, unsigned short Value, unsigned short Index, unsigned char Direction, unsigned short DataLength, unsigned char *Buffer[]);
int Disconnect (unsigned int Handle);
int main(){
char *partpath[2];
unsigned int *num;
unsigned int vid = 1110;
unsigned int pid = 45617;
unsigned int error = Search_For_Boards(vid, pid, num, partpath);
cout<<"Hello\n"<<error<<endl;
return 0;
}
And on compiling the code in the following command:
g++ C:\test.cpp -L "C:\Program Files\Analog Devices\USB Drivers" -lADI_CYUSB_USB4
I get the error
Undefined reference to Search_For_Boards(unsigned int, unsigned, int, unsigned int*, char**)
meaning apparently the function prototype is not correct.
Now all this is ASSUMING that i can use the DLL in a C++ program. Seeing the document for VB6 function declaration made me thinking if my assumption is wrong. So my 2 questions are :
1) Is my assumption correct?
2) If the assumption is correct, What is the blunder i am doing here? I feel like I linked the library properly and to my best declared the prototype according to what is described.
I write a parser for some data structure, after hours of debugging I found out that the problem is Visual Studio doesn't interpret the structures as I tell it. It seems some "padding" is used
struct foo {
unsigned char a; //0x00
unsigned char b; //0x01
unsigned int c; //0x02
unsigned int d; //0x06
unsigned int e; //0x0A
unsigned int f; //0x0E
//0x12
};
I expected "sizeof(foo)=4*4+2=18" but I get "sizeof(foo)=20". Is there any possibility to turn padding off just for this special struct? I tried
__declspec(align(1)) struct foo { ...
but it does not work. Thank you for your help.
Use the #pragma pack directive for that:
#pragma pack(push, 1)
struct foo {
// etc..
};
#pragma pack(pop)
Visual Studio 2010 has #pragma pack to do what you're looking for.
I searched this forum already and found a same question but it didn't solve and not even gave any clue in solving my problem. I am doing one project in which i am using Templates.
Firstly i used C++ map like this
typedef map<int ,cal_point*> p_mMap2D;
and it worked perfectly. Then i tried to make a GUI using Qt, but when i used "QMap", it gave an error that
typedef QMap<int ,cal_point*> p_mMap2D;
Error 25 error C2632: 'char' followed by 'char' is illegal C:\Qt
\4.7.4\include\QtCore\qglobal.h 897
Then i tried to use only map as i used before but still it is giving error. I searched net but didn't get any clue related to it. If i don't use Qt then its working perfectly.
Code from qtglobal.h
QT_BEGIN_INCLUDE_NAMESPACE
typedef unsigned char uchar;
typedef unsigned short ushort;
typedef unsigned int uint;
typedef unsigned long ulong;
QT_END_INCLUDE_NAMESPACE
Inside /src/corelib/global/qglobal.h Qt 4.8.5 contains following strings:
# define QT_BEGIN_INCLUDE_NAMESPACE }
# define QT_END_INCLUDE_NAMESPACE namespace QT_NAMESPACE {
And when preprocessor expands this macro with for example QT_NAMESPACE=qt result will be:
}
typedef unsigned char uchar;
typedef unsigned short ushort;
typedef unsigned int uint;
typedef unsigned long ulong;
namespace qt {
Looks like an error of definition QT_BEGIN_INCLUDE_NAMESPACE and QT_END_INCLUDE_NAMESPACE.
It is hard to tell because you have not included the definition of cal_point*, but the problem is where it is defined or somewhere among those lines. Check them. It might be in an external file that makes it break, and so on.
I am having a bit of trouble with the following include:
#include <ntddscsi.h>
When I compile (using NetBean 7.1 & Cygwin C++ compiler), I am told that I need to define "SCSI_PASS_THROUGH" before I can use it... in ntddscsi.h however, it is defined:
typedef struct _SCSI_PASS_THROUGH {
SHORT Length;
CHAR ScsiStatus;
CHAR PathId;
CHAR TargetId;
CHAR Lun;
CHAR CdbLength;
CHAR SenseInfoLength;
CHAR DataIn;
LONG DataTransferLength;
LONG TimeOutValue;
LONG_PTR DataBufferOffset;
LONG SenseInfoOffset;
CHAR Cdb[16];
} SCSI_PASS_THROUGH, *PSCSI_PASS_THROUGH;
Anyone have any idea what on earth is going wrong??
This might happen if you have circular dependencies, or for example LONG_PTR is not defined anywhere.