Substitution Occurs in a True / False Statement in C

Issue

• Substitution Occurs in a True / False Statement in C
• (csh) In one line “if” statement, substition still occurs in command even if expr is false.

• if (expr) command:

  # csh
  # if 0 echo $SHLIB_PATH
  SHLIB_PATH: Undefined variable.
  # exit
  

• SHLIB_PATH: Undefined variable.

• If the express is false no operations should be done on the command, but in the example substitution is still erroneously attempted resulting in an error message.
• I should get the same results from a single line “if” statement as from a equivalent multiline “if” statement.