undefined reference to `swprintf'

[lefebvresam]

Using C++20 option std::format:

uint8_t Display::getVersion(string& version) {
    struct image_version iver;
    if (boot_get_current_version(&iver)) {
        ERROR("Cannot read version number");
        return 1;
    }
    version = std::format("%u.%u.%u+%lu", iver.iv_major, iver.iv_minor, +iver.iv_revision, +iver.iv_build_num);
    return 0;
}

gives:

/usr/local/gcc-arm/bin/../lib/gcc/arm-none-eabi/13.3.1/../../../../arm-none-eabi/bin/ld: /usr/local/gcc-arm/bin/../lib/gcc/arm-none-eabi/13.3.1/../../../../arm-none-eabi/lib/thumb/v8-m.main+fp/softfp/libc_nano.a(libc_a-wcsftime.o): in function `__strftime.isra.0':
wcsftime.c:(.text.__strftime.isra.0+0x2fa): undefined reference to `swprintf'
/usr/local/gcc-arm/bin/../lib/gcc/arm-none-eabi/13.3.1/../../../../arm-none-eabi/bin/ld: wcsftime.c:(.text.__strftime.isra.0+0x32c): undefined reference to `swprintf'
/usr/local/gcc-arm/bin/../lib/gcc/arm-none-eabi/13.3.1/../../../../arm-none-eabi/bin/ld: wcsftime.c:(.text.__strftime.isra.0+0x390): undefined reference to `swprintf'
/usr/local/gcc-arm/bin/../lib/gcc/arm-none-eabi/13.3.1/../../../../arm-none-eabi/bin/ld: wcsftime.c:(.text.__strftime.isra.0+0x608): undefined reference to `swprintf'
/usr/local/gcc-arm/bin/../lib/gcc/arm-none-eabi/13.3.1/../../../../arm-none-eabi/bin/ld: wcsftime.c:(.text.__strftime.isra.0+0x700): undefined reference to `swprintf'
/usr/local/gcc-arm/bin/../lib/gcc/arm-none-eabi/13.3.1/../../../../arm-none-eabi/bin/ld: /usr/local/gcc-arm/bin/../lib/gcc/arm-none-eabi/13.3.1/../../../../arm-none-eabi/lib/thumb/v8-m.main+fp/softfp/libc_nano.a(libc_a-wcsftime.o):wcsftime.c:(.text.__strftime.isra.0+0x834): more undefined references to `swprintf' follow
collect2: error: ld returned 1 exit status
ninja: build stopped: subcommand failed.

[JohnK1987]

1. you are using c++20 what is not officially supported in Mbed as i remember.
2. I remember you had set "target.c_lib": "small". Have you also tried "target.c_lib": "std"?

[lefebvresam]

Then I have:

l/build/develop/memory_banks.json
/usr/local/gcc-arm/bin/../lib/gcc/arm-none-eabi/13.3.1/../../../../arm-none-eabi/bin/ld: source/hmc20.elf section `.text' will not fit in region `FLASH'
/usr/local/gcc-arm/bin/../lib/gcc/arm-none-eabi/13.3.1/../../../../arm-none-eabi/bin/ld: region `FLASH' overflowed by 71436 bytes
collect2: error: ld returned 1 exit status
ninja: build stopped: subcommand failed.
Building failed

Alternative is old school but ugly:

uint8_t Display::getVersion(string& version) {
    struct image_version iver;
    if (boot_get_current_version(&iver)) {
        ERROR("Cannot read version number");
        return 1;
    }
    if (version.capacity() < 20) {
        ERROR("The string has not enough capacity");
        return 1;
    }
    sprintf(version.data(), "%u.%u.%u+%lu", +iver.iv_major, +iver.iv_minor, +iver.iv_revision, +iver.iv_build_num);
    return 0;
}

[JohnK1987]

The new error is probably related to the change from small to std because the std occupied more flash memory.

[lefebvresam]

I try to avoid advanced libs like streaming operator << etc, it will dramatically increase memory use.