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'''[wiki:GraspSwClibraries libcli.a and libcli2.a]''' |
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[[TracNav(GraspContents)]] |
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The cli in libcli stands for Command Line Interpreter. Just as the shell script level [wiki:GraspSwDemoScripts demo scripts] get their parsing support for the common [wiki:GraspSwCommandSyntax command syntax used throughout STARGRASP] from [wiki:GraspSwDemoFunctions functions], all software written in C including command line utilities, servers, and the embedded C in the controller use '''libcli''' functions to parse user command line strings and text based communication protocol messages. |
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Newer code generally uses '''libcli2.''' A few older programs such as the [wiki:GraspExtrasOperationsStatserv status server] still use '''libcli.''' The primary difference is in the definition of '''Function'''. When writing a program that uses libcli, a C function of this type must be created for each command that the program should handle. A '''Function''' must return the enumerated type '''PASSFAIL''' (provided by libcli) which can either be a value '''PASS''' or '''FAIL'''. No further error code returns are supported by libcli. The newer '''libcli2''' defines the arguments for '''Function''' in the same way as a C program's main: |
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{{{ |
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typedef PASSFAIL Function (int argc, const char* argv[]); |
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}}} |
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with the name of the command which invokes Function as argv[0]. The older '''libcli''' does not pass the command name itself to Function. Instead, it passes any and all arguments to the command as a single string: |
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{{{ |
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typedef PASSFAIL Function (const char* args); |
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}}} |
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The above describes libcli's primary function: looking up a command in a table of defined "Function"s and invoking the correct one. The library has other functions, such as parsing the arguments for a function and matching up and assigning values to variables in the C code for each argument. The library can also be used to pass a command line over a pipe or network socket to a program called '''Director''' which is a customized shell for multiplexing several separate command line interpreters together. Each of those command line interpreters are called "Agents" and libcli contains functions to facilitate building an Agent process. |
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The functions within libcli are described within the [http://software.cfht.hawaii.edu/director/director-man.html Director/Agent documentation]: |
