#### ${tool}_start Procedure ¶

Starts a particular tool. For an interactive tool, `${tool}_start` starts and initializes the tool, leaving the tool up and running for the test cases; an example is `gdb_start`, the start function for GDB. For a batch-oriented tool, `${tool}_start` is optional; the recommended convention is to let `${tool}_start` run the tool, leaving the output in a variable called `comp_output`. Test scripts can then analyze `$comp_output` to determine the test results. An example of this second kind of start function is `gcc_start`, the start function for GCC.

DejaGnu itself does not call `${tool}_start`. The initialization module `${tool}_init.exp` must call `${tool}_start` for interactive tools; for batch-oriented tools, each individual test script calls `${tool}_start` (or makes other arrangements to run the tool).

> `${tool}_start`