[SOLVED] Bug report: Printf AND RTT prototype

Zeetah · Nov 21st 2018, 2:01am

Printf over RTT has an improperly declared prototype and/or the function name is incorrect and/or comment is incorrect. This is with Release 4.10a Build 201810203.37618 Windows x64

SEGGER_RTT.h has the following prototype:

Source Code: SEGGER_RTT.h

/*********************************************************************
*
* RTT printf functions (require SEGGER_RTT_printf.c)
*
**********************************************************************
*/
int SEGGER_RTT_printf(unsigned BufferIndex, const char * sFormat, ...);

I looked and there is no SEGGER_RTT_printf.c

However, there is a SEGGER_RTT_SES.c and it has a printf() that looks about right.

Source Code: SEGGER_RTT_SES.c

int printf(const char *fmt,...) {
char buffer[128];
va_list args;
va_start (args, fmt);
int n = vsnprintf(buffer, sizeof(buffer), fmt, args);
SEGGER_RTT_Write(0, buffer, n);
va_end(args);
return n;
}

I tested this printf, without a prototype, and it works just fine.

SEGGER - Nino · Nov 23rd 2018, 10:12am

Hello,

Thank you for your inquiry.
The comment is correct. You can find the SEGGER_RTT_printf.c in the latest version either in your J-Link install folder under Samples\RTT
or on the RTT website: segger.com/products/debug-prob…about-real-time-transfer/

The SEGGER_RTT_SES.c should not be used here. That file defines the printf handling in case of RTT is used.

Best regards,

Nino

Zeetah · Nov 24th 2018, 6:49am

Sorry but I'm confused.

When I used printf() in SEGGER_RTT_SES.c, I saw output in the Debug Terminal pane of Embedded Studio.

It looks like SEGGER_RTT_printf.c in the Samples\RTT does the same thing.

When should I use which one?
What is wrong with using printf() in SEGGER_RTT_SES.c?

Thanks.

Zeetah · Dec 11th 2018, 7:47am

Looks like to use NewLib, I need to use SEGGER_RTT_printf.c because SEGGER_RTT_SES.c relies on SES library/header files.

Please consider this not an issue.

Thank you for the support.

SEGGER - Nino · Dec 11th 2018, 8:58am

Hello,

Thank you for the update.
This thread will be closed now.

Best regards,
Nino

[SOLVED] Bug report: Printf AND RTT prototype

[SOLVED] Bug report: Printf AND RTT prototype

Source Code: SEGGER_RTT.h

Source Code: SEGGER_RTT_SES.c

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