Questions tagged [const-char]
68 questions
3
votes
2 answers
Proper memory cleanup with c_str() and const char *
I have a function that takes a (char* const*). The data I am provided is in a std::string. So I'm doing this:
void blahblah(std::string str)
{
const char * cc = str.c_str();
ConstCharFunction(&cc);
}
This works well. My question is do I need…
user3758015
- 119
- 1
- 9
3
votes
1 answer
How to pass string between c++ and c# with null characters inside?
In C++ I have some strings, for example
string str = "a\0b\0c";
And I need to pass this string to C# without losing data after "\0",and from c# pass to C++ also without losing data.
Can you help me?
Pavlo Denys
- 81
- 1
- 6
3
votes
7 answers
How do I properly turn a const char* returned from a function into a const char** in C?
In short, I would like to do this:
const char **stringPtr = &getString();
However, I understand that you can't & on rvalues. So I'm stuck with this:
const char *string = getString();
const char **stringPtr = &string;
I can live with two lines. Am…
spirulence
- 701
- 3
- 11
3
votes
3 answers
How to convert const char* to const WCHAR*
I have something like this:
if(GetFileAttributesW("C:\\Directory")!="INVALID_FILE_ATTRIBUTES") {...}
I get error: cannot convert 'const char*' to 'const WCHAR*' for argument '1' to 'DWORD GetFileAttributesW(const WCHAR*)'
How to convert const char*…
burtek
- 2,576
- 7
- 29
- 37
2
votes
1 answer
Qt 5 Logging - defining category with QLoggingCategory
I have a problem with QLoggingCategory(const char * category).
When I use it like:
QString rt = "3";
QString sv = "P";
QLoggingCategory dailyLogger(QString(rt+sv+"Logger").toStdString().c_str());
it doesn't work (my custom message handler doesn't…
lazare
- 31
- 3
2
votes
2 answers
casting away the constness using const_cast
No. This question in NOT duplicate of
When should static_cast, dynamic_cast, const_cast and reinterpret_cast be used?
The question asked here is no ways similar to the link described as duplicate.
First question :
I am using const_cast below for…
anurag86
- 1,635
- 1
- 16
- 31
2
votes
1 answer
const char pointer declaration in struct
I'm trying to do this, but my compiler won't let me:
struct {
const char* string = "some text";
} myAnonymousStruct;
I believe it's because no assignments can be made in a struct declaration - they're supposed to be made in…
Codesmith
- 5,779
- 5
- 38
- 50
1
vote
3 answers
How come XDrawString doesn't take "const char *"?
looking at the declaration for XDrawString from X11, it is
int XDrawString(Display *display, Drawable d, GC gc,
int x, int y, char *string, int length);
How come the 6th argument is type "char *" instead of "const char *"? Does…
user102008
- 30,736
- 10
- 83
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1
vote
1 answer
How do I convert a String into a char in C++
I want to convert a string that is inside a vector of strings (vector) into a char.
The vector would look something like the following: lons = ["41", "23", "N", "2", "11" ,"E"]. I would like to extract the "N" and the "E" to convert them into a…
Nhenon
- 49
- 7
1
vote
3 answers
How can I join a char to a constant char*?
I have a function that joins two constant char* and returns the result. What I want to do though is join a char to a constant char* eg
char *command = "nest";
char *halloween = join("hallowee", command[0]); //this gives an error
char *join(const…
pnizzle
- 6,243
- 4
- 52
- 81
1
vote
1 answer
String and Variable combination
i m a beginner in c++ and i have a question.
how can i combine a variable and a string in the folowing line.
QMessageBox::Question(this,"Report", "the Report is in Path: " + pdfPath + "saved, do you want to open it", QMessageBox::Yes |…
Boumo
- 19
- 2
1
vote
0 answers
converting const char to string isn't working
Trying to convert type const char to type std::string. All the examples I've seen are for const char *. If I change my type to * the dc.at will fail.
The conversion to string is failing. I've been trawling for an hour, it can't be that hard, I'm…
Dan
- 2,304
- 6
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- 69
1
vote
2 answers
Trying to connect to ROS using rosserial-windows . Error with the IP address
I am trying to connect to ROS using rosserial windows. I am following the tutorial given on the ROS website (http://wiki.ros.org/rosserial_windows/Tutorials/Hello%20World)
here is what my code looks like:
// ConsoleApplication1.cpp : Defines the…
sdcguy
- 11
- 1
1
vote
2 answers
Different results for QString to const char*
I have a code snippet to test a code bug.
#include
#include
int main(int argc, char *argv[])
{
QCoreApplication a(argc, argv);
QString name = QString("Lucy");
QString interest =…
user3857893
- 63
- 1
- 5
1
vote
1 answer
C++ MFC missing const char* variable
So I have that simple code inside button click method:
std::stringstream ss;
unsigned counter = 0;
while(true)
{
ss.clear();
ss << DEFAULT_USER_CONFIG_NAME << " " << ++counter;
const char* name = ss.str().c_str();
MessageBox(name);
…
Arrekin
- 95
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