View source for Printf() does not work or causes strange effects

== Problem ==
Sometimes a simple printf() (sprintf(), snprintf(), fprintf()) function call seems to fail since no CCS ( or terminal or buffer) output occurs. In other cases a printf() conversion of integer or float seems to affect data on the stack or delays or stalls the code execution for a long time.

Please check the following steps:

== Solution ==
# missing include <stdio.h>.<br> Since printf() is a variadic function, calling such a function without a valid prototype invokes undefined behavior
# missing trailing CR LF (\r\n) or flush.<br> By default the CCS output is line-buffered. To see the outputs close the line with CR LF or fflush(stdout);
# insufficient stack size.<br> Make sure the stack size is at least <span style="color: red;">0x800</span>.
# insufficient heap size.<br> Each stream needs its own heap buffer. Make sure the heap size is at least <span style="color: red;">0x400</span> per stream.
# Avoid C I/O inside interrupt handler functions.<br> C I/O functions are not reentrant and can cause a huge delay.
# Stop-mode C I/O causes huge delay.<br> The current C I/O ABI works by setting a breakpoint at C$$IO$$. When this breakpoint is hit, the CPU is halted. The debugger then reads the contents of the .cio buffer through JTAG, performs the requested C I/O operation, writes the results back to .cio, and restarts the CPU. This is a very expensive operation in terms of cycles, and can be very disruptive in real-time systems. 



== Additional Links ==
More details can be found on TI's Wiki page:

http://processors.wiki.ti.com/index.php/Tips_for_using_printf

https://e2e.ti.com/support/microcontrollers/stellaris_arm/f/471/t/99381

https://e2e.ti.com/support/microcontrollers/tiva_arm/f/908/t/199796

 [[category:Software]]