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Available only if LIB_STR_CFG_FP_EN is DEF_ENABLED in lib_cfg.h (see section 5-1).
Notes / Warnings
For any unsuccessful string format or errors, an invalid string of question marks ('?') will be formatted, where the number of question marks is determined by the number of digits (nbr_dig) and number of decimal point digits (nbr_dp) to format. Also, whenever an invalid string is formatted for any reason, a NULL pointer is returned.
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