TMS320F28379D: sprintf works in a C++ function but not in a C function

Benjamin Couillard

Part Number: TMS320F28379D

I have a while (1) loop in my main.cpp file

while (1)

{

    if (++i >= 2000000uL)
    {
          i = 0;
          sprintf(debugStr, "Coffee from C++ function\n");
          g_sci.Tx(debugStr, strnlen(debugStr));
          printDummy(debugStr);
          g_sci.Tx(debugStr, strnlen(debugStr));
    }
}

my printDummy function is a C function in a separate C file. I used the extern "C" keywork in my main.cpp file.

extern "C" {

#include "dummy.h"
}

void printDummy(char * dummy)
{
    sprintf(dummy, "Coffee from C function\n");
}

The printf from the C++ code works fine. However, the printf from the C code writes some random values in the string.
I have open source C code that I need to debug so that's why I used the sprintf function from both C and C++ code.

I'm puzzled. This should work. The code compiles and links just fine.

I'm using the TI v22.6.0.LTS compiler in the legacy COFF mode.

My stack size is 0x2000 and heap size is 0x2000. Printf is enabled with the "nofloat" switch.

Regards

over 3 years ago

0 Benjamin Couillard over 3 years ago

Intellectual 340 points

I found the bug. I forgot to include <stdio.h>. However, I don't understand why the compiler and linker never complained.... They should have generated an error..

#include <stdio.h>


void printDummy(char * dummy)
{
    sprintf(dummy, "Coffee from C function\n");
}

0 Santosh Jha over 3 years ago in reply to Benjamin Couillard

TI__Guru 50611 points

Benjamin,

I have looped in compiler expert. Please expect response by tomorrow.

Thanks, Santosh

+1 George Mock over 3 years ago in reply to Santosh Jha

TI__Guru**** 251010 points

Benjamin Couillard said:
I don't understand why the compiler and linker never complained.... They should have generated an error..

A warning is generated by default.

C:\examples>type file.c
void printDummy(char *dummy)
{
    sprintf(dummy, "Coffee from C function\n");
}

C:\examples>cl2000 file.c
"file.c", line 3: warning: function "sprintf" declared implicitly

You can discover the ID number associated with that diagnostic ...

C:\examples>cl2000 --display_error_number file.c
"file.c", line 3: warning #225-D: function "sprintf" declared implicitly

Then use that ID number to elevate the handling of this diagnostic to an error, and thus cause the build to fail.

C:\examples>cl2000 --display_error_number --diag_error=225 file.c
"file.c", line 3: error #225-D: function "sprintf" declared implicitly
1 error detected in the compilation of "file.c".

>> Compilation failure

For more background on these compiler options, please search the C28x compiler manual for the sub-chapter titled Understanding Diagnostic Messages.

Thanks and regards,

-George

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TMS320F28379D: sprintf works in a C++ function but not in a C function