Null terminated strings in C and C++ embedded SQL applications

C and C++ null-terminated strings are handled differently, depending on the value of the LANGLEVEL precompiler option. If a host variable of one of these SQLTYPE values and declared length n is specified within an SQL statement, and the number of bytes (for character types) or double-byte characters (for graphic types) of data is k, then:

• If the LANGLEVEL option on the PREP command is SAA1 (the default):

  For Output:

  If...

  Then...

  k > n

  n characters are moved to the target host variable, SQLWARN1 is set to 'W', and SQLCODE 0 (SQLSTATE 01004). No null-terminator is placed in the string. If an indicator variable was specified with the host variable, the value of the indicator variable is set to k.

  k = n

  k characters are moved to the target host variable, SQLWARN1 is set to 'N', and SQLCODE 0 (SQLSTATE 01004). No null-terminator is placed in the string. If an indicator variable was specified with the host variable, the value of the indicator variable is set to 0.

  k < n

  k characters are moved to the target host variable and a null character is placed in character k + 1. If an indicator variable was specified with the host variable, the value of the indicator variable is set to 0.

  For input:

  When the database manager encounters an input host variable of one of these SQLTYPE values that does not end with a null-terminator, it will assume that character n+1 will contain the null-terminator character.

• If the LANGLEVEL option on the PREP command is MIA:

  For output:

  If...

  Then...

  k >= n

  n - 1 characters are moved to the target host variable, SQLWARN1 is set to 'W', and SQLCODE 0 (SQLSTATE 01501). The nth character is set to the null-terminator. If an indicator variable was specified with the host variable, the value of the indicator variable is set to k.

  k + 1 = n

  k characters are moved to the target host variable, and the null-terminator is placed in character n. If an indicator variable was specified with the host variable, the value of the indicator variable is set to 0.

  k + 1 < n

  k characters are moved to the target host variable, n - k -1 blanks are appended on the right starting at character k + 1, then the null-terminator is placed in character n. If an indicator variable was specified with the host variable, the value of the indicator variable is set to 0.

  For input:

  When the database manager encounters an input host variable of one of these SQLTYPE values that does not end with a null character, SQLCODE -302 (SQLSTATE 22501) is returned.