CCS/TCI6638K2K: crash issue with fprintf usage

The starting advice for these issues is MORE COWBELL!

Sorry, wrong context, I meant increase the stack size.

Hi Keith,
Thanks for quick reply.. I have separate task which does only file I/O with stack size configured(100K bytes) lot more than required.

Are you checking to make sure that fopen() returns a valid file descriptor?

Yes Keith, I am validating the file descriptor.
FYI, pasting the code below.
fp = fopen("test.txt","w");
if(fp == 0)
{
System_printf("Error opening file");
}
fprintf(fp,"IQ");
fclose(fp);

With regard to fprintf failing to work at all, please try the suggestions in the article Tips For Using Printf.

Sri N said:

when i executes the fprintf line in the code i get the below error.

Can't find a source file at "/tmp/TI_MKLIBW8MzNW/SRC/exit.c

This occurs due to a low level detail of how the RTS library is built in older versions of the compiler.  CCS tries to find the source to the RTS function, fprintf in this case, and fails to find it.  The solution is to upgrade to a more recent compiler version.

Thanks and regards,

-George

After performing the System_printf(), code proceeds to perform the fprintf() anyway. You need an exit from the function or at least to skip over those commands.

Depending on the implementation of System_printf() (e.g., output to UART by DMA) the fprintf() and subsequent crash could occur before you see the message.

On a side note, I recommend changing the if statement to:

if (fp == NULL)

rather than checking for 0.

Why should he check for NULL instead of 0? It is perfectly legal C.

c-faq.com/.../macsochange.html

(Good catch of the bug, though!)

Keith Barkley said:

Why should he check for NULL instead of 0? It is perfectly legal C.

c-faq.com/.../macsochange.html

That is true but for purposes of readability and self-documentation, I like to show that the variable is a pointer, not an ordinary numeric variable that you would use for general purpose calculations. Hence the distinction I draw between 0 and NULL.