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    • snprintf() Outputs Empty String

    Posted by spflanze on 2016-04-11 05:42

    The code:

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    char *pstrResp;
pstrResp = pvPortMalloc( 23 );
snprintf( pstrResp, 23, "%8.6g", .0123 );

    Produces an empty string in pstrResp. In it there is only the NULL terminator in the first character position. I expected .0123 to be converted to characters and placed in pstrRes. What is wrong here?

    The pstrResp points to a RAM location so it is known that pvPortMalloc() succeded.
    If I include a string using %s specifier the string does show up in pstrResp.

    Processor is STM32F373VCT
    This is an STM32CubeMX generated project with the FREERTOS option enabled.
    The compiler is GNU.

    Reads: 14710
    Posted by tarek bouchkati on 2016-04-11 11:12 Tunisia

    check if you are using nanolib (-specs=nano.specs in Project properties > C/C++ Build > Settings > Tool Settings (TAB) > MCU GCC Linker > Miscellaneous > Linker flags)
    If it is the case, you need to enable float printf :
    -specs=nano.specs -u _printf_float

    Regards,
    Tarek

         Posted by spflanze on 2016-04-11 22:47
    That worked. Thank you 😊