What does "null-terminated" mean?

• tomiz

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  August 3, 2002 at 6:21 am

  #79165

  Hello!

  When using ADO i came across datatypes called VarChar and VarWChar. Now in the description I found out that VarWChar is a "null-terminated character string". What does that mean exactly? Couldn't find it in BOL nor the web...

  Thanks!

  /Tomi

• K. Brian Kelley

  SSC Guru

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  August 3, 2002 at 8:36 am

  #433949

  VarChar and VarWChar are variable length character strings. There needs to be something to mark the end of the string. Character 0x00 (or 0x0000 in Unicode), which means null, and wouldn't be part of any string because it has no meaning, is used to signify the end of the string. I believe in C this is used for all strings. Here is a couple of links which may make more sense than what I am saying:

  http://msdn.microsoft.com/library/en-us/odbc/htm/odbccharacter_data_and_c_strings.asp

  http://msdn.microsoft.com/library/en-us/vccore98/HTML/_core_character_strings.asp

  K. Brian Kelley

  bkelley@sqlservercentral.com

  http://www.sqlservercentral.com/columnists/bkelley/

  K. Brian Kelley
  @kbriankelley

• tomiz

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  August 4, 2002 at 5:58 am

  #433961

  Thanks!

  I think I sort of figured it out now