The D_VOID_TYPE data type means no data value is to be passed. spec treats all data as either a string or a double - the necessary type conversions are made automatically. The argument arg1_in is necessary if the command requires an input value. For the two- element composite types, arg2_in must also be provided. For array input types, arg1_in is the name of the array. For the D_VAR_ array types (except for D_VAR_STRINGARR), arg1_in can be an associative array or a declared array data type. For commands that produce an output array or composite values, array_out is the name of an array to receive the values. The declared array data types can only be used for D_VAR_ array types (except for D_VAR_STRINGARR). For commands that produce an output array of numbers (not strings or composite data types), a data group and element can be specified as grp and el, and the received data will be placed there.

taco_io("?" [, filter])

A single "?" lists all the devices available on the current NETHOST. The optional filter argument can be used to limit the contents of the returned list and is in the "usual" DOMAIN/FAMILY/MEMBER format, where the * character can be used to match patterns in any of the three fields. See the TACO db_getdevexp man page for more information.

taco_io(dev, "?")

Lists the valid commands for the named device, along with the data types of any input and/or output arguments.

taco_io(dev, "timeout", time)

Sets the remote procedure call (RPC) timeout for the indicated device. The value of time is in seconds. If time is zero, the timeout is set to its original value. The function returns the timeout value.

taco_io(dev, "udp"|"tcp")

Sets the ethernet protocol for the named device.

If there is an error in sending a command to the device, taco_io() returns -1. In addition,the variable TACO_ERR (and ESRF_ERR, if it exists) will be assigned the device server error number (or zero if there is no error). If TACO_ERR (or ESRF_ERR) has the value -1 before the call of taco_io(), no error message will be printed, although, the error message will be assigned to the variable TACO_ERR_MSG (and ESRF_ERR_MSG, if it exists). If no output argument is generated by the command, the function returns zero. If the output data type is an array or composite value, the number of elements in the array or composite value is returned. Otherwise the value generated by the command is returned.

The first time taco_io() is called with a particular device name, the device is "imported" from the server. The connection remains open until you exit spec or execute the reconfig command. (The reconfig command is called by the config macro.) The reconfig command frees all server connections, so the next time taco_io() is called the device will be "imported" again.

The complex data type D_VAR_GRPFPARR is described as follows:

struct Frame {
        double  value;
        short   output, pause;
};
struct FramePair {
        Frame   dead, live;
};
struct DevGrpFramePair {
        u_int           nb_framepair;
        FramePair       framepair;
};
struct DevGrpFramePairArray {
        u_int           length;
        DevGrpFramePair *sequence;
};


element[0] : sequence->nm_framepair
element[1] : sequence->framepair.dead.value
element[2] : sequence->framepair.dead.output
element[3] : sequence->framepair.dead.pause
element[4] : sequence->framepair.live.value
element[5] : sequence->framepair.live.output
element[6] : sequence->framepair.live.pause


ESRF devices named in the config file that are imported for motor, timer or counter control or for GPIB access can be accessed using taco_io(), although that is generally not recommended, as the user-level commands might conflict with the internal code.

The string error message associated with any errors (either from taco_io() or from the built-in C code that accesses the device servers) will be assigned to the built-in variable TACO_ERR_MSG (and ESRF_ERR_MSG, if it exists).

DATA COLLECTOR

The ESRF data collector system can be accessed using the following functions. All devices must reside on NETHOST.

taco_dc(dev, "create", cmd, data_type)

Creates a new pseudodevice for the data collector named dev having data accessed using the command cmd having data type data_type. The parameters dev, cmd and data_type are all strings. spec requires data collector devices it creates to have only one command. If the device already exists with a different command or with more than one command, the function fails. The cmd argument must be one of the commands recognized by the data collector. spec supports the following data types: