23 lines
973 B
Markdown
23 lines
973 B
Markdown
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# Shells
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Turaco-DOS reserves a portion of main memory for a "shell", a
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program which exists to load and run other programs, and handle
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their return values. This shell might be a command line, or some
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other program that manages other programs, such as a batch file
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interpreter.
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The active shell has a "resident" portion of memory, which stays
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in memory as long as the shell is active, and a "transient" portion
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of memory which is only used while the shell is not running an
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external program.
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When the shell runs a program, and that program exits, its main
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function returns a two-byte value; this value is stored in a
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specific memory address, and used by the shell as the "status"
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code for the program's exit. Like Unix, a zero value is considered
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a normal exit, with any positive value being some type of error.
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Additionaly, when running a program, the shell can provide the
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program with a sequence of arguments, which populate the two
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arguments to the main() function.
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