How can I change c standard to c99 or newer

yixing · September 20, 2023, 3:34pm

I’m trying to learn to develop hardware msp430g2553 with vscode + platformio. * However, it is shown during compilation that the c99 standard is not supported.
I tried code like:

it told me like below:

#include "msp430.h"

int main()
{
    WDTCTL = WDTPW | WDTHOLD; // Stop watchdog timer
    P2SEL &= ~(BIT2 | BIT5);
    P2SEL2 &= ~(BIT2 | BIT5);
    P2OUT |= BIT2 | BIT5;
    P2DIR |= BIT2 | BIT5;
    unsigned int L = 0, M = 0;
    while (1)
    {
        L++;
        if (1 > 0x200)
            L = 0;
        M = 0x200 - L;
        P2OUT &= ~(BIT2 | BIT5);
        for (int i = 0; i < L; i++)
        {
            P2OUT |= (BIT2 | BIT5);
        }
        for (int i = 0; i < M; i++)
            ;
    }

    return 0;
}

src\main.c: In function 'main':
src\main.c:18:9: error: 'for' loop initial declarations are only allowed in C99 mode
src\main.c:18:9: note: use option -std=c99 or -std=gnu99 to compile your code
src\main.c:22:18: error: redefinition of 'i'
src\main.c:18:18: note: previous definition of 'i' was here
src\main.c:22:9: error: 'for' loop initial declarations are only allowed in C99 mode

I do know that this problem can be avoided by changing the code,but I * But I still want to get it to support the updated c standard.

I have tried writen ‘build_flags = -std=c99’ in platform.ini ,but it not works.

I try to find blogs about this , nothing was found ,maybe i have not used right key words

My English is not very good, thank you for reading this.

Hoping discussing!

maxgerhardt · September 20, 2023, 3:36pm

That’s one part of it, but first you gotta find out what the current -std value is so that you that you can build_unflags = -std=... it.

Do so by using the project task Advanced → Verbose Build.

yixing · September 20, 2023, 3:49pm

I have added code like

build_unflags = 
    -std=c89
    -std=gnu89
    -std=c95
    -std=gnu95

but it not work
I build it ,and it tells me

PLATFORM: TI MSP430 (2.4.0) > TI LaunchPad MSP-EXP430G2553LP
HARDWARE: MSP430G2553 16MHz, 512B RAM, 16KB Flash
DEBUG: Current (mspdebug) On-board (mspdebug)
PACKAGES:
 - framework-energiamsp430 @ 1.10810.210219 (1.8.10)        
 - toolchain-timsp430 @ 1.40603.210219 (4.6.3)
LDF: Library Dependency Finder -> https://bit.ly/configure-pio-ldf
LDF Modes: Finder ~ chain, Compatibility ~ soft
Found 18 compatible libraries
Scanning dependencies...
No dependencies
Building in release mode
msp430-gcc -o .pio\build\lpmsp430g2553\src\main.c.o -c -mmcu=msp430g2553 -Os -ffunction-sections -fdata-sections -DF_CPU=16000000L -DPLATFORMIO=60111 -DENERGIA_ARCH_MSP430 -DENERGIA_MSP_EXP430G2553LP -DARDUINO=10807 -DENERGIA=10810 -Iinclude -Isrc -IC:\Users\yixing\.platformio\packages\framework-energiamsp430\cores\msp430 -IC:\Users\yixing\.platformio\packages\framework-energiamsp430\variants\MSP-EXP430G2553LP -IC:\Users\yixing\.platformio\packages\toolchain-timsp430\msp430\include src\main.c
src\main.c: In function 'main':
src\main.c:18:9: error: 'for' loop initial declarations are only allowed in C99 mode
src\main.c:18:9: note: use option -std=c99 or -std=gnu99 to compile your code       
src\main.c:22:18: error: redefinition of 'i'
src\main.c:18:18: note: previous definition of 'i' was here
src\main.c:22:9: error: 'for' loop initial declarations are only allowed in C99 mode
msp430-g++ -o .pio\build\lpmsp430g2553\FrameworkEnergia\new.cpp.o -c -fno-exceptions -fno-threadsafe-statics -mmcu=msp430g2553 -Os -ffunction-sections -fdata-sections -DF_CPU=16000000L -DPLATFORMIO=60111 -DENERGIA_ARCH_MSP430 -DENERGIA_MSP_EXP430G2553LP -DARDUINO=10807 -DENERGIA=10810 -IC:\Users\yixing\.platformio\packages\framework-energiamsp430\cores\msp430 -IC:\Users\yixing\.platformio\packages\framework-energiamsp430\variants\MSP-EXP430G2553LP -IC:\Users\yixing\.platformio\packages\toolchain-timsp430\msp430\include C:\Users\yixing\.platformio\packages\framework-energiamsp430\cores\msp430\new.cpp
msp430-gcc -o .pio\build\lpmsp430g2553\FrameworkEnergia\random.c.o -c -mmcu=msp430g2553 -Os -ffunction-sections -fdata-sections -DF_CPU=16000000L -DPLATFORMIO=60111 -DENERGIA_ARCH_MSP430 -DENERGIA_MSP_EXP430G2553LP -DARDUINO=10807 -DENERGIA=10810 -IC:\Users\yixing\.platformio\packages\framework-energiamsp430\cores\msp430 -IC:\Users\yixing\.platformio\packages\framework-energiamsp430\variants\MSP-EXP430G2553LP -IC:\Users\yixing\.platformio\packages\toolchain-timsp430\msp430\include C:\Users\yixing\.platformio\packages\framework-energiamsp430\cores\msp430\random.c
msp430-gcc -o .pio\build\lpmsp430g2553\FrameworkEnergia\usci_isr_handler.c.o -c -mmcu=msp430g2553 -Os -ffunction-sections -fdata-sections -DF_CPU=16000000L -DPLATFORMIO=60111 -DENERGIA_ARCH_MSP430 -DENERGIA_MSP_EXP430G2553LP -DARDUINO=10807 -DENERGIA=10810 -IC:\Users\yixing\.platformio\packages\framework-energiamsp430\cores\msp430 -IC:\Users\yixing\.platformio\packages\framework-energiamsp430\variants\MSP-EXP430G2553LP -IC:\Users\yixing\.platformio\packages\toolchain-timsp430\msp430\include C:\Users\yixing\.platformio\packages\framework-energiamsp430\cores\msp430\usci_isr_handler.c
msp430-gcc -o .pio\build\lpmsp430g2553\FrameworkEnergia\wiring.c.o -c -mmcu=msp430g2553 -Os -ffunction-sections -fdata-sections -DF_CPU=16000000L -DPLATFORMIO=60111 -DENERGIA_ARCH_MSP430 -DENERGIA_MSP_EXP430G2553LP -DARDUINO=10807 -DENERGIA=10810 -IC:\Users\yixing\.platformio\packages\framework-energiamsp430\cores\msp430 -IC:\Users\yixing\.platformio\packages\framework-energiamsp430\variants\MSP-EXP430G2553LP -IC:\Users\yixing\.platformio\packages\toolchain-timsp430\msp430\include C:\Users\yixing\.platformio\packages\framework-energiamsp430\cores\msp430\wiring.c
msp430-gcc -o .pio\build\lpmsp430g2553\FrameworkEnergia\wiring_analog.c.o -c -mmcu=msp430g2553 -Os -ffunction-sections -fdata-sections -DF_CPU=16000000L -DPLATFORMIO=60111 -DENERGIA_ARCH_MSP430 -DENERGIA_MSP_EXP430G2553LP -DARDUINO=10807 -DENERGIA=10810 -IC:\Users\yixing\.platformio\packages\framework-energiamsp430\cores\msp430 -IC:\Users\yixing\.platformio\packages\framework-energiamsp430\variants\MSP-EXP430G2553LP -IC:\Users\yixing\.platformio\packages\toolchain-timsp430\msp430\include C:\Users\yixing\.platformio\packages\framework-energiamsp430\cores\msp430\wiring_analog.c
msp430-gcc -o .pio\build\lpmsp430g2553\FrameworkEnergia\wiring_digital.c.o -c -mmcu=msp430g2553 -Os -ffunction-sections -fdata-sections -DF_CPU=16000000L -DPLATFORMIO=60111 -DENERGIA_ARCH_MSP430 -DENERGIA_MSP_E*** [.pio\build\lpmsp430g2553\src\main.c.o] Error 1
XP430G2553LP -DARDUINO=10807 -DENERGIA=10810 -IC:\Users\yixing\.platformio\packages\framework-energiamsp430\cores\msp430 -IC:\Users\yixing\.platformio\packages\framework-energiamsp430\variants\MSP-EXP430G2553LP -IC:\Users\yixing\.platformio\packages\toolchain-timsp430\msp430\include C:\Users\yixing\.platformio\packages\framework-energiamsp430\cores\msp430\wiring_digital.c
msp430-gcc -o .pio\build\lpmsp430g2553\FrameworkEnergia\wiring_pulse.c.o -c -mmcu=msp430g2553 -Os -ffunction-sections -fdata-sections -DF_CPU=16000000L -DPLATFORMIO=60111 -DENERGIA_ARCH_MSP430 -DENERGIA_MSP_EXP430G2553LP -DARDUINO=10807 -DENERGIA=10810 -IC:\Users\yixing\.platformio\packages\framework-energiamsp430\cores\msp430 -IC:\Users\yixing\.platformio\packages\framework-energiamsp430\variants\MSP-EXP430G2553LP -IC:\Users\yixing\.platformio\packages\toolchain-timsp430\msp430\include C:\Users\yixing\.platformio\packages\framework-energiamsp430\cores\msp430\wiring_pulse.c
msp430-gcc -o .pio\build\lpmsp430g2553\FrameworkEnergia\wiring_shift.c.o -c -mmcu=msp430g2553 -Os -ffunction-sections -fdata-sections -DF_CPU=16000000L -DPLATFORMIO=60111 -DENERGIA_ARCH_MSP430 -DENERGIA_MSP_EXP430G2553LP -DARDUINO=10807 -DENERGIA=10810 -IC:\Users\yixing\.platformio\packages\framework-energiamsp430\cores\msp430 -IC:\Users\yixing\.platformio\packages\framework-energiamsp430\variants\MSP-EXP430G2553LP -IC:\Users\yixing\.platformio\packages\toolchain-timsp430\msp430\include C:\Users\yixing\.platformio\packages\framework-energiamsp430\cores\msp430\wiring_shift.c

I noticed that my build chain didn’t specify anything standards-related. I don’t quite understand.

maxgerhardt · September 20, 2023, 4:00pm

Energia is Arduino. In your code, you try to define a main() function, but the Arduino framework already has that… so that is fundamentally wrong usage.

In any case though,

[env:lpmsp430g2553]
platform = timsp430
board = lpmsp430g2553
framework = arduino
build_flags = -std=gnu99

works fine in this case.

maxgerhardt · September 20, 2023, 4:01pm

To avoid compiling in the Arduino code alltogether, just remove the framework = ... line in the platformio.ini, then it’ll be bare-metal. This still compiles the file normally and efficiently.

[env:lpmsp430g2553]
platform = timsp430
board = lpmsp430g2553
build_flags = -std=gnu99

yixing · September 20, 2023, 4:09pm

OHHHHHHHHHH it works!
Thankyou,Thankyou,Thankyou.
just now,i try change the file neme to 'main.cpp’from ‘main.c’,and it also works (i am not understand again).

maxgerhardt · September 20, 2023, 4:16pm

The C++ language allows these variable specifications with whatever language version, so this is never illegal code.

yixing · September 20, 2023, 4:21pm

Thank you for your patience!!!