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ABAP Keyword Documentation →  ABAP - Reference →  Processing Internal Data →  Character String and Byte String Processing →  Statements for Character String and Byte String Processing 


Short Reference

Other versions: 7.31 | 7.40 | 7.54


SET BIT bitpos OF byte_string [TO val]. 


This statement sets the bit in bit position bitpos of the variable byte_string to 1 or, if specified, to the value of data object val. The other bits in byte_string remain unchanged.

The data object byte_string must be byte-like, whereas bitpos and val are numerical expression positions of operand type i. The value of bitpos must be greater than 0 and val must be either 0 or 1. Otherwise an exception that cannot be handled is raised. The bit positions in byte_string are counted from the beginning of the data object. If the value of bitpos is greater than the number of bits in byte_string, no bit is replaced and sy-subrc is set to 4.

System Fields

sy-subrc Meaning
0 A bit in data object byte_string was set at position bitpos.
4 The value of bitpos is greater than the number of bits in byte_string, therefore no bit was set.


  • If byte_string has the deep type xstring, a bit is set in the referenced byte string, not in the reference.
  • Setting single bits is especially suited to preparing operators in bit expressions.
  • The predefined function bit-set can also be used to set an individual bit.
  • Character-like data objects are also allowed for byte_string in obsolete non-Unicode programs.


In the data object hex with eight bits, the bit is set to the value 1 at the position determined by the loop counter sy-index, with all other bits set to 0. The output is "80 40 20 10 08 04 02 01".

DATA hex        TYPE x LENGTH 1. 
DATA output TYPE string. 
  CLEAR hex. 
  SET BIT sy-index OF hex. 
  output = output && |{ hex } |. 
cl_demo_output=>display( output ). 


Non-Catchable Exceptions

  • Cause: The bit position is greater than or equal to 0.
  • Cause: The value of val is not equal to 0 or 1.
    Runtime Error: BIT_NO_ZERO_OR_ONE