px4-firmware/nuttx/libc/Kconfig

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#
# For a description of the syntax of this configuration file,
# see misc/tools/kconfig-language.txt.
#
comment "Standard C Library Options"
config STDIO_BUFFER_SIZE
int "C STDIO buffer size"
default 64
---help---
Size of buffers using within the C buffered I/O interfaces.
(printf, putchar, fwrite, etc.).
config STDIO_LINEBUFFER
bool "STDIO line buffering"
default y
---help---
Flush buffer I/O whenever a newline character is found in
the output data stream.
config NUNGET_CHARS
int "Number unget() characters"
default 2
---help---
Number of characters that can be buffered by ungetc() (Only if NFILE_STREAMS > 0)
config LIB_HOMEDIR
string "Home directory"
default "/"
depends on !DISABLE_ENVIRON
---help---
The home directory to use with operations like such as 'cd ~'
source libc/math/Kconfig
config NOPRINTF_FIELDWIDTH
bool "Disable sprintf support fieldwidth"
default n
---help---
sprintf-related logic is a
little smaller if we do not support fieldwidthes
config LIBC_FLOATINGPOINT
bool "Enable floating point in printf"
default n
---help---
By default, floating point
support in printf, sscanf, etc. is disabled.
choice
prompt "Newline Options"
default EOL_IS_EITHER_CRLF
---help---
This selection determines the line terminating character that is used.
Some environments may return CR as end-of-line, others LF, and others
both. If not specified, the default is either CR or LF (but not both)
as the line terminating charactor.
config EOL_IS_CR
bool "EOL is CR"
config EOL_IS_LF
bool "EOL is LF"
config EOL_IS_BOTH_CRLF
bool "EOL is CR and LF"
config EOL_IS_EITHER_CRLF
bool "EOL is CR or LF"
endchoice
config LIBC_STRERROR
bool "Enable strerror"
default n
---help---
strerror() is useful because it decodes 'errno' values into a human readable
strings. But it can also require a lot of memory. If this option is selected,
strerror() will still exist in the build but it will not decode error values.
This option should be used by other logic to decide if it should use strerror()
or not. For example, the NSH application will not use strerror() if this
option is not selected; perror() will not use strerror() is this option is not
selected (see also NSH_STRERROR).
config LIBC_STRERROR_SHORT
bool "Use short error descriptions in strerror()"
default n
depends on LIBC_STRERROR
---help---
If this option is selected, then strerror() will use a shortened string when
it decodes the error. Specifically, strerror() is simply use the string that
is the common name for the error. For example, the 'errno' value of 2 will
produce the string "No such file or directory" is LIBC_STRERROR_SHORT
is not defined but the string "ENOENT" is LIBC_STRERROR_SHORT is defined.
config LIBC_PERROR_STDOUT
bool "perror() to stdout"
default n
---help---
POSIX requires that perror() provide its output on stderr. This option may
be defined, however, to provide perror() output that is serialized with
other stdout messages.
config ARCH_LOWPUTC
bool "Low-level console output"
default "y"
---help---
architecture supports low-level, boot time console output
config LIB_SENDFILE_BUFSIZE
int "sendfile() buffer size"
default 512
---help---
Size of the I/O buffer to allocate in sendfile(). Default: 512b
config ARCH_ROMGETC
bool "Support for ROM string access"
default n
---help---
In Harvard architectures, data accesses and instruction accesses
occur on different busses, perhaps concurrently. All data accesses
are performed on the data bus unless special machine instructions
are used to read data from the instruction address space. Also, in
the typical MCU, the available SRAM data memory is much smaller that
the non-volatile FLASH instruction memory. So if the application
requires many constant strings, the only practical solution may be
to store those constant strings in FLASH memory where they can only
be accessed using architecture-specific machine instructions.
If ARCH_ROMGETC is defined, then the architecture logic must export
the function up_romgetc(). up_romgetc() will simply read one byte
of data from the instruction space.
If ARCH_ROMGETC, certain C stdio functions are effected: (1) All
format strings in printf, fprintf, sprintf, etc. are assumed to lie
in FLASH (string arguments for %s are still assumed to reside in SRAM).
And (2), the string argument to puts and fputs is assumed to reside
in FLASH. Clearly, these assumptions may have to modified for the
particular needs of your environment. There is no "one-size-fits-all"
solution for this problem.
config ARCH_OPTIMIZED_FUNCTIONS
bool "Enable arch optimized functions"
default n
---help---
Allow for architecture optimized implementations of certain library
functions. Architecture-specific implementations can improve overall
system performance.
if ARCH_OPTIMIZED_FUNCTIONS
config ARCH_MEMCPY
bool "memcpy()"
default n
---help---
Select this option if the architecture provides an optimized version
of memcpy().
config MEMCPY_VIK
bool "Vik memcpy()"
default n
depends on !ARCH_MEMCPY
---help---
Select this option to use the optimized memcpy() function by Daniel Vik.
Select this option for improved performance at the expense of increased
size. See licensing information in the top-level COPYING file.
if MEMCPY_VIK
config MEMCPY_PRE_INC_PTRS
bool "Pre-increment pointers"
default n
---help---
Use pre-increment of pointers. Default is post increment of pointers.
config MEMCPY_INDEXED_COPY
bool "Array indexing"
default y
---help---
Copying data using array indexing. Using this option, disables the
MEMCPY_PRE_INC_PTRS option.
config MEMCPY_64BIT
bool "64-bit memcpy()"
default n
---help---
Compiles memcpy() for architectures that suppport 64-bit operations
efficiently.
endif
config ARCH_MEMCMP
bool "memcmp()"
default n
---help---
Select this option if the architecture provides an optimized version
of memcmp().
config ARCH_MEMMOVE
bool "memmove()"
default n
---help---
Select this option if the architecture provides an optimized version
of memmove().
config ARCH_MEMSET
bool "memset()"
default n
---help---
Select this option if the architecture provides an optimized version
of memset().
config MEMSET_OPTSPEED
bool "Optimize memset() for speed"
default n
depends on !ARCH_MEMSET
---help---
Select this option to use a version of memcpy() optimized for speed.
Default: memcpy() is optimized for size.
config MEMSET_64BIT
bool "64-bit memset()"
default n
depends on MEMSET_OPTSPEED
---help---
Compiles memset() for architectures that suppport 64-bit operations
efficiently.
config ARCH_STRCHR
bool "strchr()"
default n
---help---
Select this option if the architecture provides an optimized version
of strchr().
config ARCH_STRCMP
bool "strcmp()"
default n
---help---
Select this option if the architecture provides an optimized version
of strcmp().
config ARCH_STRCPY
bool "strcpy()"
default n
---help---
Select this option if the architecture provides an optimized version
of strcpy().
config ARCH_STRNCPY
bool "strncpy()"
default n
---help---
Select this option if the architecture provides an optimized version
of strncpy().
config ARCH_STRLEN
bool "strlen"
default n
---help---
Select this option if the architecture provides an optimized version
of strlen().
config ARCH_STRNLEN
bool "strlen()"
default n
---help---
Select this option if the architecture provides an optimized version
of strnlen().
config ARCH_BZERO
bool "bzero()"
default n
---help---
Select this option if the architecture provides an optimized version
of bzero().
endif
comment "Non-standard Helper Functions"
config LIB_KBDCODEC
bool "Keyboard CODEC"
default y
---help---
In NuttX, a keyboard/keypad driver is simply a character driver that
may have an (optional) encoding/decoding layer on the data returned
by the character driver. A keyboard may return simple text data
(alphabetic, numeric, and punctuaction) or control characters
(enter, control-C, etc.). We can think about this the normal
"in-band" keyboard data stream. However, in addition, most
keyboards support actions that cannot be represented as text data.
Such actions include things like cursor controls (home, up arrow,
page down, etc.), editing functions (insert, delete, etc.), volume
controls, (mute, volume up, etc.) and other special functions. We
can think about this as special, "out-of-band" keyboard commands.
In this case, some special encoding may be required to multiplex
the in-band text data and out-of-band command streams.
This option enables the functions that implement the encoding and
decoding of keyboard data. These are the interfaces prototyped in
include/nuttx/input/kbd_codec.h. While not correctly a part of
the C library, it is included here because the decoding side of this
interface must be accessible by end user programs.