# # 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 field widths. config LIBC_FLOATINGPOINT bool "Enable floating point in printf" default n ---help--- By default, floating point support in printf, sscanf, etc. is disabled. config LIBC_IOCTL_VARIADIC bool "Enable variadic ioctl()" default n ---help--- By default, NuttX implements the "old style," three-parameter, ioctl() interface with this function prototype: int ioctl(int fd, int req, unsigned long arg); That function is implemented as part of the VFS. If LIBC_IOCTL_VARIADIC is selected, then an additional compatibility layer will be provided in the C library. The enabled, then function prototype will become: int ioctl(int fd, int req, ...); The ioctl() is not controlled by any standard so it is really arbitrary which format you used. You may select the variadic function prototype with this option. That will slightly increase code size and ioctl() processing time. It will not support a variable number of arguments and it still always expects to see a third argument of type 'unsigned long'. The only benefit of this alternative function signature is that it may provide greater compatibility if you are porting code from other platforms that use the variadic ioctl() function. WARNING: Use of this option could cause subtle system errors is the third argument is omitted or if the sizeof the thread argument is anything other than sizeof (unsigned long). Most small integers will be promoted to 'int'. The following assertion appears in ioctl(): DEBUGASSERT(sizeof(int) == sizeof(unsigned long) && sizeof(FAR void *) == sizeof(unsigned long)); Do not enable this option if the above is not true. 32-bit ARM should pass this test with all three types having sizeof(type) == 4 bytes. 'float' should also be tested. But 'long long' and 'double' are out of the question! Don't event try to pass them. And what will happen if no third argument is passed? In most cases, this should just result in a garbage value for arg. But you may discover cases where something worse happens! config LIB_RAND_ORDER int "Order of the random number generate" default 1 range 1 3 ---help--- The order of the random number generator. 1=fast but very bad random numbers, 3=slow but very good random numbers. 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_EXECFUNCS bool "Enable exec[l|v] / posix_spawn() Support" default n depends on !BINFMT_DISABLE ---help--- Enable support for the exec[l|v] family of functions that can be used to start other programs, terminating the current program and the posix_spawn() familty of functions that can be used start other programs without terminating the current program. The typical usage of the exec[l|v] functions is (1) first call vfork() to create a new thread, then (2) call exec[l|v] to replace the new thread with a program from the file system. NOTE 1: This two step process start is completely unnecessary in NuttX and is provided only for compatibily with Unix systems. These functions are essentially just wrapper functions that (1) call the non-standard binfmt function 'exec', and then (2) exit(0). Since the new thread will be terminated by the exec[l|v] call, it really served no purpose other than to suport Unix compatility. The posix_spawn() functions do not have this inefficiency. NOTE 2: Support for exec[l|v] and posix_spawn() is conditional because they require additional support for symbol tables that will not be available in the typical system. if LIBC_EXECFUNCS config EXECFUNCS_HAVE_SYMTAB bool "Have symbol table" default n if BUILD_KERNEL default y if !BUILD_KERNEL ---help--- If you have a system symbol table, then you must select this option in order to use it. Symbol tables are required in most cases in order to like executable programs to the base code. if EXECFUNCS_HAVE_SYMTAB config EXECFUNCS_SYMTAB string "Symbol table used by exec[l|v]" default "g_symtab" ---help--- The exec[l|v] and posix_spawn() functions are wrapper functions that call the non-standard binfmt function 'exec'). The binfmt function 'exec' needs to have (1) a symbol table that provides the list of symbols exported by the base code, and (2) the number of symbols in that table. This selection provides the name of that symbol table. config EXECFUNCS_NSYMBOLS int "Number of Symbols in the Table" default 0 ---help--- The exec[l|v] and posix_spawn() functions are wrapper functions that call the non-standard binfmt function 'exec'). The binfmt function 'exec' needs to have (1) a symbol table that provides the list of symbols exported by the base code, and (2) the number of symbols in that table. This selection provides the number of symbols in the symbol table. endif # EXECFUNCS_HAVE_SYMTAB endif # LIBC_EXECFUNCS config POSIX_SPAWN_PROXY_STACKSIZE int "Spawn Stack Size" default 1024 ---help--- If posix_spawn[p]() and task_spawn() use I/O redirection options, they will require an intermediary/proxy task to muck with the file descriptors. This configuration item specifies the stack size used for the proxy. Default: 1024 bytes. config TASK_SPAWN_DEFAULT_STACKSIZE int "Default task_spawn Stack Size" default 2048 depends on !ARCH_ADDRENV ---help--- The actual size to use for the child task's stack can be set with task_spawnattr_setstacksize(). This value specifies the default stack size to use if task_spawnattr_setstacksize() is not used. Default: 2048. 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 LIBC_TMPDIR string "Temporary file directory" default "/tmp" depends on FS_WRITABLE ---help--- If a write-able file system is selected, this string will be provided to specify the full path to a directory where temporary files can be created. This would be a good application of RAM disk: To provide temporary storage for application data. config LIBC_MAX_TMPFILE int "Maximum size of a temporary file path" default 32 depends on FS_WRITABLE ---help--- If a write-able file system is selected, then temporary file may be supported at the path provided by LIBC_TMPDIR. The tmpnam() interface keeps a static copy of this last filename produced; this value is the maximum size of that last filename. This size is the size of the full file path. config ARCH_LOWPUTC bool "Low-level console output" default "y" ---help--- architecture supports low-level, boot time console output config LIBC_LOCALTIME bool "localtime API call support" default "n" depends on !DISABLE_ENVIRON ---help--- localtime API call support Logic currently depends on file system support with, at a minimum, these files in the zoneinfo directory: GMT and posixrules. An additional timezone file is required for any additional, local time zone(s) and the environment variable TZ must be set to the name of that timezone file when tzset() is called. See https://www.iana.org/time-zones . See also apps/system/zoneinfo which provides a framework for incorporating the TZ database into a NuttX build. if LIBC_LOCALTIME config LIBC_TZ_MAX_TIMES int "Maximum number of times in timezone" default 370 ---help--- Timezone files with more than this number of times will not be usedi (tmecnt). Warning: Some files in IANA TZ database include many times. The current posixrules file, for example, has timecnt = 236. The value of TX_MAX_ITMES in the tzfile.h header file on my Linux system is 370, the default used here. You may want to reduce this value for a smaller footprint. config LIBC_TZ_MAX_TYPES int "Maximum number of TZ types" default 20 ---help--- Maximum number of local time types. You may want to reduce this value for a smaller footprint. config LIBC_TZDIR string "zoneinfo directory path" default "/etc/zoneinfo" ---help--- This is the full path to the location where the TZ database is expected to be found. endif config TIME_EXTENDED bool "Add day of week, year support" default "n" depends on !LIBC_LOCALTIME ---help--- Selecting TIME_EXTENDED adds tm_wday, tm_yday and tm_isdst to the tm struct. This allows integration with 3rd party libraries that expect the tm struct to contain these members. Note: tm_isdst is always 0 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 buses, 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 is selected, 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 # MEMCPY_VIK 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 # ARCH_OPTIMIZED_FUNCTIONS comment "Non-standard Library Support" if BUILD_PROTECTED || BUILD_KERNEL config LIB_USRWORK bool "User mode worker thread" default n depends on !DISABLE_SIGNALS ---help--- User space work queues can also be made available for deferred processing in the NuttX kernel build. if LIB_USRWORK config LIB_USRWORKPRIORITY int "User mode priority worker thread priority" default 100 ---help--- The execution priority of the user-mode priority worker thread. Default: 100 config LIB_USRWORKPERIOD int "User mode worker thread period" default 100000 ---help--- How often the lower priority worker thread checks for work in units of microseconds. Default: 100*1000 (100 MS). config LIB_USRWORKSTACKSIZE int "User mode worker thread stack size" default 2048 ---help--- The stack size allocated for the lower priority worker thread. Default: 2K. endif # LIB_USRWORK endif # BUILD_PROTECTED || BUILD_KERNEL config LIB_KBDCODEC bool "Keyboard CODEC" default n ---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.). 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. Some special encoding may be required to multiplex these two classes of data. 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. config LIB_SLCDCODEC bool "Segment LCD CODEC" default n ---help--- In NuttX, a character-oriented, segment LCD (SLCD) driver is simply a character device that may have an (optional) encoding/decoding layer on the data provided to the SLCD driver. The application may provide simple text data (alphabetic, numeric, and punctuaction) or control characters (enter, control-C, etc.). However, in addition, most SLCDs support actions that cannot be represented as text data. Such actions include things like cursor controls (home, up arrow, page down, etc.) and other special functions (e.g., blinking). Some special encoding may be required to multiplex these two classes of data. This option enables the functions that implement the encoding and decoding of SLCD data. These are the interfaces prototyped in include/nuttx/lcd/slcd_codec.h. While not correctly a part of the C library, it is included here because the encoding side of this interface must be accessible by end user programs.