QByteArray problem
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@aha_1980
There is my full code , this is just test unit. I need exactly int value in it , and how i understand '\xFF' will store char in it ?#include <QCoreApplication> #include <QByteArray> #include <QString> #include <QTextStream> int main(int argc, char *argv[]) { QTextStream cin(stdin); cin.setCodec("CP866"); QTextStream cout(stdout); cout.setCodec("CP866"); QCoreApplication a(argc, argv); QByteArray ba; ba.resize(4); ba[0] = 0xFF; ba[1] = 0xFF; ba[2] = 0xF; ba[3] = 0xF; char tdi[16]; int b=0; for(int i=0;i<4;i++) { uint16_t mask = 0x8; for (int j = 0; j < 4; j++) { tdi[b] = (ba[i] & mask) ? '1' : '0'; mask >>= 1; b++; } } for(int i=0;i<16;i++) { cout<<tdi[i]<<endl; } cout<<tdi<<endl; cout<<ba[0]<<endl; //cout<<sizeof(tdi)<<endl; return a.exec(); } -
@Zizione
In addition to the solutions offered by @VRonin....I am not a C++-er, but I believe in your case your can use the
Usuffix to make your constant valuesunsigned intand thus convertible tounsigned char:ba[0] = 0xFFU;?
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@Zizione
In addition to the solutions offered by @VRonin....I am not a C++-er, but I believe in your case your can use the
Usuffix to make your constant valuesunsigned intand thus convertible tounsigned char:ba[0] = 0xFFU;?
@JonB said in QByteArray problem:
@Zizione
In addition to the solutions offered by @VRonin....I am not a C++-er, but I believe in your case your can use the
Usuffix to make your constant valuesunsigned intand thus convertible tounsigned char:ba[0] = 0xFFU;?
Yeah, but
baissigned char...Qt has to stay free or it will die.
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@JonB said in QByteArray problem:
@Zizione
In addition to the solutions offered by @VRonin....I am not a C++-er, but I believe in your case your can use the
Usuffix to make your constant valuesunsigned intand thus convertible tounsigned char:ba[0] = 0xFFU;?
Yeah, but
baissigned char...@aha_1980
true, but the warning one gets withba[0] = 0xFFis not about usigned and signed char but rather betweenintandchar0xFFU==unsigned char(0xFF)==uchar(0xFF)!=0xFFthe implicit conversation to ba[0] does not "drop" information
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@aha_1980
true, but the warning one gets withba[0] = 0xFFis not about usigned and signed char but rather betweenintandchar0xFFU==unsigned char(0xFF)==uchar(0xFF)!=0xFFthe implicit conversation to ba[0] does not "drop" information
@J.Hilk have you tried?
QByteArray ba; ba.resize(4); ba[0] = char(0xFF); // no warning ba[1] = 0xFFU; // warning: implicit conversion changes signedness: 'unsigned int' to 'char' ba[2] = 0xFF; // warning: implicit conversion changes signedness: 'int' to 'char'Edit: screenshot
Qt has to stay free or it will die.
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@J.Hilk have you tried?
QByteArray ba; ba.resize(4); ba[0] = char(0xFF); // no warning ba[1] = 0xFFU; // warning: implicit conversion changes signedness: 'unsigned int' to 'char' ba[2] = 0xFF; // warning: implicit conversion changes signedness: 'int' to 'char'Edit: screenshot
@aha_1980 said in QByteArray problem:
@J.Hilk have you tried?
I always do, well 95%, before I post ;-)
to be honest, I'm surprised about the uint part.
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@aha_1980 said in QByteArray problem:
@J.Hilk have you tried?
I always do, well 95%, before I post ;-)
to be honest, I'm surprised about the uint part.
then you can be surprised about the uchar() part too.
But the biggest surprise: your code will not even compile in gcc and clang because of line 65.
And one more hint: your code will crash as you access invalid index in ba ;)
Qt has to stay free or it will die.
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then you can be surprised about the uchar() part too.
But the biggest surprise: your code will not even compile in gcc and clang because of line 65.
And one more hint: your code will crash as you access invalid index in ba ;)
@aha_1980 said in QByteArray problem:
@J.Hilk
But the biggest surprise: your code will not even compile in gcc and clang because of line 65.I saw you using linux in the screen shot and testet that there than, and noticed it too
And one more hint: your code will crash as you access invalid index in ba ;)
nope doesn't crash, ignore the project name its my test anything project x).
!resize is apparently not a necessity?
Edit:
also ignore value 0, I commeted that line out, to run it with gcc, so theres a random value.
// ba[0] = unsigned char(0xFF);
Be aware of the Qt Code of Conduct, when posting : https://forum.qt.io/topic/113070/qt-code-of-conduct
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@aha_1980 said in QByteArray problem:
@J.Hilk
But the biggest surprise: your code will not even compile in gcc and clang because of line 65.I saw you using linux in the screen shot and testet that there than, and noticed it too
And one more hint: your code will crash as you access invalid index in ba ;)
nope doesn't crash, ignore the project name its my test anything project x).
!resize is apparently not a necessity?
Edit:
also ignore value 0, I commeted that line out, to run it with gcc, so theres a random value.
// ba[0] = unsigned char(0xFF);@J.Hilk said in QByteArray problem:
resize is apparently not a necessity?
Ah, my fault: "If an assignment is made beyond the end of the byte array, the array is extended with resize() before the assignment takes place."
A big difference to QVector or QList here.
