Combining char array into other data types

[PaperPilot]

It's me again:

I have to write some classes that have a pointer to chars and must combine them into other data types. For example:

void IcInterface::setData(char *inBufr)
{
     float mach = *inBufr;
     inBufr += 4;
     float altitude = *inBufr;
     inBufr += 4;
     short runwayNumber = *inBufr;
}
 

Every method I tried gave me a run-time error on the target machine (a PPC runnning vxWorks).

Any ideas?

Thanks in advance.

[willakawill]

Hi, is this one of the ways to tried to make it work?

void IcInterface::setData(char *inBufr)
{
   float mach = float(*inBufr);
   inBufr += 4;
   float altitude = float(*inBufr);
   inBufr += 4;
   short runwayNumber = short(*inBufr);
}

[PaperPilot]

Hi, is this one of the ways to tried to make it work?

void IcInterface::setData(char *inBufr)
{
   float mach = float(*inBufr);
   inBufr += 4;
   float altitude = float(*inBufr);
   inBufr += 4;
   short runwayNumber = short(*inBufr);
}

I couldn't get past:

float mach = float(*inBufr);

I tried casting, but didn't get any farther. Moving the data into an array didn't help either. The only one that worked was:

bufrPtr = reinterpret_cast<bool *>( inBufr );

But it only casts a char to bool.

[willakawill]

What could you not get past. The code that I posted works on my machine. What are the values stored in your char array?

[horace1]

I couldn't get past:

float mach = float(*inBufr);

I tried casting, but didn't get any farther. Moving the data into an array didn't help either. The only one that worked was:

bufrPtr = reinterpret_cast<bool *>( inBufr );

But it only casts a char to bool.

perhaps you have an old C++ compiler, try the C cast

void IcInterface::setData(char *inBufr)
{
   float mach = (float)*inBufr;
   inBufr += 4;
   float altitude = (float)*inBufr;
   inBufr += 4;
   short runwayNumber = (short)*inBufr;
}
 

[PaperPilot]

What could you not get past. The code that I posted works on my machine. What are the values stored in your char array?

I am getting data from the user interface (a Java program running on a PC) via TCP. When I received Mach which I know to be 0.63, the routine displayed 63. The altitude was 24905, but displayed 70.

I finally got it to work using the following:

float IcInterface::getMach()
{
  return getFloat(buffer_, 0);      //mach
}
 
float IcInterface::getAltitude()
{  
  return getFloat(buffer_, 4);     //altitude;
}
 
float getFloat(char* buf, int from)
{
    buf+=from;
 
    float tempVal;
    memcpy(&tempVal, buf , sizeof(float));
 
    return tempVal;
}

The code for boolean and short data is similar. The trick was to use memcpy instead of a cast.

Thanks for helping me out.