105 lines
4.4 KiB
Plaintext
105 lines
4.4 KiB
Plaintext
#
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# For a description of the syntax of this configuration file,
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# see the file kconfig-language.txt in the NuttX tools repository.
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#
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config LIBC_IOCTL_VARIADIC
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bool "Enable variadic ioctl()"
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default n
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---help---
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By default, NuttX implements the "old style," three-parameter,
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ioctl() interface with this function prototype:
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int ioctl(int fd, int req, unsigned long arg);
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That function is implemented as part of the VFS. If
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LIBC_IOCTL_VARIADIC is selected, then an additional compatibility
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layer will be provided in the C library. The enabled, then function
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prototype will become:
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int ioctl(int fd, int req, ...);
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The ioctl() is not controlled by any standard so it is really
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arbitrary which format you used. You may select the variadic
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function prototype with this option. That will slightly increase
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code size and ioctl() processing time. It will not support a
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variable number of arguments and it still always expects to see a
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third argument of type 'unsigned long'. The only benefit of this
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alternative function signature is that it may provide greater
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compatibility if you are porting code from other platforms that use
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the variadic ioctl() function.
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WARNING: Use of this option could cause subtle system errors is
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the third argument is omitted or if the sizeof the thread argument
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is anything other than sizeof (unsigned long). Most small integers
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will be promoted to 'int'. The following assertion appears in ioctl():
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DEBUGASSERT(sizeof(int) == sizeof(unsigned long) &&
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sizeof(FAR void *) == sizeof(unsigned long));
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Do not enable this option if the above is not true. 32-bit ARM
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should pass this test with all three types having sizeof(type) == 4
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bytes. 'float' should also be tested. But 'long long' and 'double'
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are out of the question! Don't event try to pass them.
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And what will happen if no third argument is passed? In most cases,
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this should just result in a garbage value for arg. But you may
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discover cases where something worse happens!
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config LIB_SENDFILE_BUFSIZE
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int "sendfile() buffer size"
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default 512
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---help---
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Size of the I/O buffer to allocate in sendfile(). Default: 512b
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comment "Non-standard Library Support"
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config LIB_CRC64_FAST
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bool "Fast CRC64"
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default n
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---help---
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Enable the CRC64 lookup table to compute the CRC64 faster.
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config LIB_KBDCODEC
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bool "Keyboard CODEC"
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default n
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---help---
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In NuttX, a keyboard/keypad driver is simply a character driver that
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may have an (optional) encoding/decoding layer on the data returned
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by the character driver. A keyboard may return simple text data
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(alphabetic, numeric, and punctuaction) or control characters
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(enter, control-C, etc.). However, in addition, most keyboards
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support actions that cannot be represented as text data. Such
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actions include things like cursor controls (home, up arrow,
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page down, etc.), editing functions (insert, delete, etc.), volume
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controls, (mute, volume up, etc.) and other special functions.
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Some special encoding may be required to multiplex these two classes
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of data.
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This option enables the functions that implement the encoding and
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decoding of keyboard data. These are the interfaces prototyped in
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include/nuttx/input/kbd_codec.h. While not correctly a part of
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the C library, it is included here because the decoding side of this
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interface must be accessible by end user programs.
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config LIB_SLCDCODEC
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bool "Segment LCD CODEC"
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default n
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---help---
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In NuttX, a character-oriented, segment LCD (SLCD) driver is simply
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a character device that may have an (optional) encoding/decoding
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layer on the data provided to the SLCD driver. The application may
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provide simple text data (alphabetic, numeric, and punctuaction) or
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control characters (enter, control-C, etc.). However, in addition,
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most SLCDs support actions that cannot be represented as text data.
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Such actions include things like cursor controls (home, up arrow,
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page down, etc.) and other special functions (e.g., blinking). Some
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special encoding may be required to multiplex these two classes of
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data.
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This option enables the functions that implement the encoding and
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decoding of SLCD data. These are the interfaces prototyped in
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include/nuttx/lcd/slcd_codec.h. While not correctly a part of the C
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library, it is included here because the encoding side of this
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interface must be accessible by end user programs.
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