nuttx/libs/libc/stdio/Kconfig

151 lines
4.6 KiB
Plaintext

#
# For a description of the syntax of this configuration file,
# see the file kconfig-language.txt in the NuttX tools repository.
#
menu "Standard C I/O"
config STDIO_DISABLE_BUFFERING
bool "Disable STDIO Buffering"
default n
---help---
Tiny systems may need to disable all support for I/O buffering in
order to minimize the memory footprint.
NOTE that even if STDIO buffering is enabled, you can still disable
buffering by setting CONFIG_STDIO_BUFFER_SIZE=0 or dynamically
through the setvbuf() interface. In this case, however, memory
used for buffering will be eliminated, of course, but there will be
no reduction in static code size. Only setting
CONFIG_STDIO_DISABLE_BUFFERING will reduce static code size.
The setvbuf() interface is not available if
CONFIG_STDIO_DISABLE_BUFFERING is selected.
if !STDIO_DISABLE_BUFFERING
config STDIO_BUFFER_SIZE
int "STDIO buffer size"
default 64
---help---
Size of buffers using within the C buffered I/O interfaces (printf,
putchar, fwrite, etc.). This function sets the initial I/O buffer
size. Zero disables I/O buffering initially. Any buffer size may
be subsequently modified using setvbuf().
config STDIO_LINEBUFFER
bool "STDIO line buffering"
default y
---help---
Sets the default behavior to flush buffered I/O whenever a newline
character is found in the output data stream. This setting just
sets the initial default behavior of all streams. The behavior of
an individual stream can be changed via setvbuf().
endif # !STDIO_DISABLE_BUFFERING
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 LIBC_PRINT_LEGACY
bool "Enable legacy printf logic"
default n
---help---
By default, printf (and friends) are implemented using a port from
newlib-nano. That port can be signifcantly smaller, especially if
floating support is enabled. This option is available, however,
to revert to the legacy printf version is so desired.
config LIBC_FLOATINGPOINT
bool "Enable floating point in printf"
default n
---help---
By default, floating point support in printf, sscanf, etc. is
disabled. This option will enable floating point support.
config LIBC_LONG_LONG
bool "Enable long long support in printf"
default y if !DEFAULT_SMALL
default n if DEFAULT_SMALL
---help---
Enables support for long long formats in printf, sscanf, etc. is
enabled. This is enabled by default but if you are trying to
reduce the FLASH footprint, then disabling this feature is one
option. The FLASH saves comes not from disabling the long long
formats, but rather from omitting the large long long arithmetic
libraries that will be drawn into the build if long long support
is enabled.
NOTE: This setting has no effect if the underlying architecture
cannot support long long types
config LIBC_NUMBERED_ARGS
bool "Enable numbered arguments in printf"
default n
depends on (LIBC_FLOATINGPOINT || LIBC_LONG_LONG) && !LIBC_PRINT_LEGACY
---help---
Enables support for numbered arguments in printf.
printf("%3$s %3$s %1$s %2$s\n", "1", "2", "3"); --> "3 3 1 2"
printf("%3$*2$.*1$f\n", 4, 8, 1.234567); --> " 1.2346"
Attention: Mixing of numbered and sequential arguments in one
format string is not allowed according to POSIX.
config LIBC_NL_ARGMAX
int "Maximum number of numbered arguments for printf"
default 16
range 9 999999
depends on LIBC_NUMBERED_ARGS
---help---
Applies only if there are numbered arguments in your format string.
The number of sequential arguments isn't affected.
Will be copied into stdio POSIX macro NL_ARGMAX.
Attention: Increasing this value will increase stack usage
of printf.
config LIBC_SCANSET
bool "Scanset support"
default n
---help---
Add scanset support to sscanf().
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 character.
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 MEMCPY_VIK
bool "Vik memcpy()"
default n
depends on !LIBC_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.
endmenu #Standard C I/O