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Return word length of fixed-point registered data type


extern int ssGetDataTypeFxpWordLength (SimStruct *S, DTypeId



SimStruct representing an S-function block.


Data type ID of the registered fixed-point data type for which you want to know the word length.


This function returns the word length of the fixed-point data type designated by dataTypeId. This function does not return the word length of the container of the data type. To get the container word length, use ssGetDataTypeFxpContainWordLen:

  • If the registered data type is fixed point, this function returns the total word length including any sign bits, integer bits, and fractional bits.

  • If the registered data type is ScaledDouble, this function returns the word length of the nonoverridden data type.

  • If registered data type is single or double, this function errors out.

This function errors out when ssGetDataTypeIsFxpFltApiCompat returns FALSE.


To use this function, you must include fixedpoint.h and fixedpoint.c. For more information, see Structure of the S-Function.




An sfix24_En10 data type has a word length of 24, but is actually stored in 32 bits during simulation. For this signal,

  • ssGetDataTypeFxpWordLength returns 24, which is the data type word length in bits.

  • ssGetDataTypeFxpContainWordLen returns 32, which is the storage container word length in bits.

  • ssGetDataTypeStorageContainerSize or sizeof( ) returns 4, which is the storage container size in bytes.

TLC Functions


Introduced before R2006a

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