Tornado

5
Shell
-> ?shConfig SH_GET_TASK_IO off
->
-> printf("Hello World!\n")
value = 13 = 0xd
->
The shell reports the printf( ) result, indicating that 13 characters have been
printed. The output, however, goes to the target’s standard output, not to the shell.
To determine the current configuration, use shConfig. If you issue the command
without an argument, all parameters are listed. Use an argument to list only one
parameter.
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-> ?shConfig SH_GET_TASK_IO
SH_GET_TASK_IO = off
For more information, see on shConfig, see WindSh Environment Variables, p.155.
The standard input and output are only redirected for the function called from
WindSh. If this function spawns other tasks, the input and output of the spawned
tasks are not redirected to WindSh. To have all I/O redirected to WindSh, you can
start the target server with the options -C -redirectShell.
5.3.2 Data Types
The most significant difference between the shell C-expression interpreter and a C
compiler lies in the way that they handle data types. The shell does not accept any
C declaration statements, and no data-type information is available in the symbol
table. Instead, an expression’s type is determined by the types of its terms.
Unless you use explicit type-casting, the shell makes the following assumptions
about data types:
■
■
In an assignment statement, the type of the left hand side is determined by the
type of the right hand side.
If floating-point numbers and integers both appear in an arithmetic
expression, the resulting type is a floating-point number.
■
Data types are assigned to various elements as shown in Table 5-9.
A constant or variable can be treated as a different type than what the shell
assumes by explicitly specifying the type with the syntax of C type-casting.
Functions that return values other than integers require a slightly different typecasting;
see Function Calls, p.179. Table 5-10 shows the various data types available
in the shell C interpreter, with examples of how they can be set and referenced.
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