MsysIoAlloc

This function allocates a MIL I/O command list and initializes it. An I/O command list allows you to schedule commands to change the state of a bit of an I/O command register at a specified time or counter value. You can route the state of the bit, for example, to an auxiliary output signal to control a connected device at a required moment.

To schedule commands, the I/O command list uses an internal counter to count clock ticks or transitions that occur on a signal specified as the counter source. When allocating an I/O command list, you must specify the counter source that will be used to schedule commands. The counter source can be either a clock, which allows you to schedule commands in time, or a specified signal, which allows you to schedule commands based on the number of transitions that occur on the signal. The latter case allows you to schedule commands, for example, based on the positional information provided by the output signal of a rotary decoder. To schedule commands with the I/O command list, use MsysIoCommandRegister().

To modify or inquire I/O command list settings, use MsysIoControl() and MsysIoInquire(). When an I/O command list is no longer required, you should free it using MsysIoFree().

[Matrox-4sight-GP]

This function is only available on Matrox 4Sight GPm.

Note that this function reference has not been updated for a MIL system added during a MIL update. Refer to the MIL system's release note to see which MIL system’s documentation you should use in its place and any possible differences.

Parameters

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This function reference has not been updated for the selected MIL system. To show the content of this page, choose a second MIL system; refer to the MIL system's release note to see which MIL system’s documentation to choose and any possible differences.

Parameters

SysId INQ

Specifies the identifier of the MIL system on which to allocate the I/O command list.

For specifying the system
Value	Description	MIL system-specific tooltip (†)
M_DEFAULT_HOST	Specifies the default Host system of the current MIL application. This Host system must have been allocated on Matrox 4Sight GPm. (summarize) Specifies the default Host system of the current MIL application. (more details...)	†	a
MIL system identifier	Specifies a valid system identifier, previously allocated using MsysAlloc(). [Matrox 4Sight GP] The system must be a Host system allocated on the Matrox 4Sight GPm platform. (summarize) Specifies a valid system identifier, previously allocated using MsysAlloc(). (more details...)	†	a

IoCmdListNum INQ

Specifies the index of the I/O command list to allocate. Note that you cannot allocate a command list with the same index as one that has already been allocated. This parameter can be set to one of the following values:

For specifying the I/O command list's index
Value	Description	MIL system-specific tooltip (†)
M_DEFAULT	Same as M_IO_COMMAND_LIST1.	†	a
M_IO_COMMAND_LIST1	Allocates the first I/O command list.	†	a
M_IO_COMMAND_LIST2	Allocates the second I/O command list.	†	a

Type INQ

Specifies the type of I/O command list to allocate. This parameter can be set to the following value:

For specifying the type of I/O command list
Value	Description	MIL system-specific tooltip (†)
M_IO_COMMAND_LIST	Specifies a general I/O command list.	†	a

CounterSrc INQ

Specifies the signal to use as the counter source. The counter source will affect the units that you should use to specify, for example, when a registered command should be executed (MsysIoCommandRegister()). This parameter can be set to one of the following values:

For specifying the counter source
Value	Description	MIL system-specific tooltip (†)
M_DEFAULT	Same as M_CLOCK.	†	a
M_AUX_IOn	Specifies to use auxiliary input signal n as the counter source, where n is the number for one of the auxiliary input signals. When specifying this counter source, schedule commands in terms of number of transitions that occur on the input signal. To change which signal transition will increment the counter, use MsysIoControl() with M_IO_COMMAND_COUNTER_ACTIVATION (by default, it is set to low-to-high transitions). [Matrox 4Sight GP] For the Matrox 4Sight GPm, n can be a value from 8 to 15. (summarize) Specifies to use auxiliary input signal n as the counter source, where n is the number for one of the auxiliary input signals. (more details...)	†	a
M_CLOCK	Specifies to use your hardware's clock signal as a counter source. When specifying this counter source, schedule commands in terms of seconds. The specified number of seconds will be internally converted to the same units as the clock. To inquire the frequency of the clock signal, use MsysIoInquire() with M_CLOCK_FREQUENCY. (summarize) Specifies to use your hardware's clock signal as a counter source. (more details...)	†	a
M_ROTARY_ENCODERn	Specifies to use the output of rotary decoder n as the counter source, where n is the number of the rotary decoder. When specifying this counter source, schedule commands in terms of number of transitions that occur on the rotary decoder's output signal (MsysControl() with M_ROTARY_ENCODER_OUTPUT_MODE). [Matrox 4Sight GP] For the Matrox 4Sight GPm, n can be either 1 or 2. (summarize) Specifies to use the output of rotary decoder n as the counter source, where n is the number of the rotary decoder. (more details...)	†	a

IoCmdListSysIdPtr

Specifies the address of the variable in which to write the I/O command list identifier. Since the MsysIoAlloc() function also returns the I/O command list identifier, you can set this parameter to M_NULL.

If allocation is successful, the I/O command list's identifier is written into the variable. If allocation fails, M_NULL is written into the variable.

Return value

The returned value is the I/O command list identifier if the allocation is successful. If allocation fails, M_NULL is returned.

Compilation information

Header	Include mil.h.
Library	Use mil.lib.
DLL	Requires mil.dll.