j (Execute If - Else)
The j command conditionally executes one of the specified commands, depending on the evaluation of a given expression.
j Expression Command1 ; Command2
j Expression 'Command1' ; 'Command2'
Parameters
Expression
The expression to evaluate. If this expression evaluates to a nonzero value, Command1 is executed. If this expression evaluates to zero, Command2 is executed. For more information about the syntax of this expression, see Numerical Expression Syntax.
Command1
The command string to be executed if the expression in Expression evaluates to a nonzero value (TRUE). You can combine multiple commands by surrounding the command string with single straight quotation marks ( ' ) and separating commands by using semicolons. If the command string is a single command, the single quotation marks are optional.
Command2
The command string to be executed if the expression in Expression evaluates to zero (FALSE). You can combine multiple commands by surrounding the command string with single straight quotation marks ( ' ) and separating commands by using semicolons. If the command string is a single command, the single quotation marks are optional.
Environment
| Item | Description |
|---|---|
| Modes | User mode, kernel mode |
| Targets | Live, crash dump |
| Platforms | All |
Remarks
You cannot add a semicolon or additional commands after the j command. If a semicolon appears after Command2, everything after the semicolon is ignored.
The following command displays the value of eax if MySymbol is equal to zero and displays the values of ebx and ecx otherwise.
0:000> j (MySymbol=0) 'r eax'; 'r ebx; r ecx'
You could omit the single quotation marks around r eax, but they make the command easier to read. If you want to omit one of the commands, you can include empty quotation marks or omit the parameter for that command, as in the following commands.
0:000> j (MySymbol=0) ''; 'r ebx; r ecx'
0:000> j (MySymbol=0) ; 'r ebx; r ecx'
You can also use the j command inside other commands. For example, you can use a j command to create conditional breakpoints.
0:000> bp `mysource.cpp:143` "j (poi(MyVar)>0n20) ''; 'gc' "
This style of conditional breakpoint is no longer recommended, as a simpler form is now available in the debugger. For more information about the syntax of conditional breakpoints, see Setting a Conditional Breakpoint.