egd_channel_info(3) [debian man page]
EGD_CHANNEL_INFO(3) EEGDEV library manual EGD_CHANNEL_INFO(3) NAME
egd_channel_info - Get various information about a particular channel SYNOPSIS
#include <eegdev.h> int egd_channel_info(const struct eegdev* dev, int stype, unsigned int index, int fieldtype, ...); DESCRIPTION
egd_channel_info() provides different type of information about the channel at the index index of the group specified by stype of the device referenced by dev. As described for egd_acq_setup(3), stype specifies the type of channel. It must one of the values returned by egd_sensor_type(3). The information returned by the function is defined by the variable list of argument. This list is composed of successive couple grouping one field type identifier specifying the feature to be get and a pointer to a value whose type depends on the previous field type. The list must finish by EGD_END. The field identifers can be the following (The expected corresponding pointer type is provided in parenthesis): EGD_LABEL (char*) Name of the channel. The pointed array should be long enough to hold 32 characters (including the null termination character). EGD_ISINT (int*) Indicates whether the data provided by the channel are integer or floating point. (zero indicates floating point, non-zero indicates integer). EGD_MM_I (int32_t*) Returns in an array of 2 int32_t the minimal and maximal values that the channel can deliver (If the channel deliver floating point data, these values can be underestimated due to overflow) EGD_MM_F (float*) Returns in an array of 2 float values the minimal and maximal values that the channel can deliver (If the channel deliver double floating point data, these values can be underestimated due to overflow) EGD_MM_D (double*) Returns in an array of 2 double values the minimal and maximal values that the channel can deliver. EGD_UNIT (char*) Unit in which the channel data is expressed. The pointed array should be long enough to hold 16 characters (including the null ter- mination character). EGD_TRANSDUCTER (char*) Transducter type of the sensor. The pointed array should be long enough to hold 128 characters (including the null termination char- acter). EGD_PREFILTERING (char*) Information about the filters already applied on data. The pointed array should be long enough to hold 128 characters (including the null termination character). RETURN VALUE
The function returns 0 in case of succes. Otherwise, -1 is returned and errno is set accordingly. ERRORS
egd_channel_info() will fail if: EINVAL dev is NULL, stype is an invalid sensor type, index is bigger than the maximal number of channel in the group, any field identifier is unknown or any pointer used is NULL. THREAD SAFETY
egd_channel_info() is thread-safe. SEE ALSO
egd_acq_setup(3), egd_sensor_type(3) EPFL
2010 EGD_CHANNEL_INFO(3)
Check Out this Related Man Page
Tcl_GetStdChannel(3) Tcl Library Procedures Tcl_GetStdChannel(3) __________________________________________________________________________________________________________________________________________________ NAME
Tcl_GetStdChannel, Tcl_SetStdChannel - procedures for retrieving and replacing the standard channels SYNOPSIS
#include <tcl.h> Tcl_Channel Tcl_GetStdChannel(type) Tcl_SetStdChannel(channel, type) ARGUMENTS
int type (in) The identifier for the standard channel to retrieve or modify. Must be one of TCL_STDIN, TCL_STDOUT, or TCL_STDERR. Tcl_Channel channel (in) The channel to use as the new value for the specified standard channel. _________________________________________________________________ DESCRIPTION
Tcl defines three special channels that are used by various I/O related commands if no other channels are specified. The standard input channel has a channel name of stdin and is used by read and gets. The standard output channel is named stdout and is used by puts. The standard error channel is named stderr and is used for reporting errors. In addition, the standard channels are inherited by any child processes created using exec or open in the absence of any other redirections. The standard channels are actually aliases for other normal channels. The current channel associated with a standard channel can be retrieved by calling Tcl_GetStdChannel with one of TCL_STDIN, TCL_STDOUT, or TCL_STDERR as the type. The return value will be a valid channel, or NULL. A new channel can be set for the standard channel specified by type by calling Tcl_SetStdChannel with a new channel or NULL in the channel argument. If the specified channel is closed by a later call to Tcl_Close, then the corresponding standard channel will automatically be set to NULL. If Tcl_GetStdChannel is called before Tcl_SetStdChannel, Tcl will construct a new channel to wrap the appropriate platform-specific stan- dard file handle. If Tcl_SetStdChannel is called before Tcl_GetStdChannel, then the default channel will not be created. If one of the standard channels is set to NULL, either by calling Tcl_SetStdChannel with a NULL channel argument, or by calling Tcl_Close on the channel, then the next call to Tcl_CreateChannel will automatically set the standard channel with the newly created channel. If more than one standard channel is NULL, then the standard channels will be assigned starting with standard input, followed by standard out- put, with standard error being last. See Tcl_StandardChannels for a general treatise about standard channels and the behaviour of the Tcl library with regard to them. SEE ALSO
Tcl_Close(3), Tcl_CreateChannel(3), Tcl_Main(3), tclsh(1) KEYWORDS
standard channel, standard input, standard output, standard error Tcl 7.5 Tcl_GetStdChannel(3)