Redirect stdout in C++

[robosoft]

Posted on January 25, 2008 at 03:43

Redirect stdout in C++

[robosoft]

Posted on May 17, 2011 at 09:49

Hi,

I use the KEIL Realview MDK-ARM

I want to define a functionpointer in the __FILE struct (stdio.h).

By changing this functionpointer in my mainprogram I can redirect stdout to some device.

To do this I changed the file retarget.c to following

 

#include

 

 

extern ''C'' {

 

struct __FILE {

 

int handle;

 

int *(*stdoutProc)(int ch); //THIS IS THE FUNCTIONPOINTER I CREATED

 

};

 

 

FILE __stdout;

 

FILE __stdin;

 

 

 

InitStdOut(int *MyStdOut(int Ch)) {

 

__stdout.stdoutProc = MyStdOut;

 

}

 

 

int fputc (int ch, FILE *f) {

 

__stdout.stdoutProc(ch);

 

return(ch);

 

}

 

} //extern C

 

I did not test the code, so maybe the code doesn't do the thing I want to do, but however I can compile it without errors !

When I rename all the files to *.cpp, to use the compilers C++ extentions, I have the error (at the line FILE __stdout;)

error #70: incomplete type is not allowed

How can I add a functionpointer to the __FILE struct in C++ environment ????

Thank you !

[mark9]

Posted on May 17, 2011 at 09:49

You should not modify the struct. To redirect stdout (or stdin, stderr) the standard way is

console = freopen(''\MYLOGFILE.TXT'',''r+'',stdout); // ''r+'' means read/write

assuming you have already written the low level drivers for your file system or IO stream.

[robosoft]

Posted on May 17, 2011 at 09:49

Thanks for response !

I think its better to write my own printf function.

Luc