AVRLibc

AVR Libc
1 User Manual
2 Library Reference
AVR Libc Library Reference
- 2 <alloca.h>: Allocate space in the stack
- 2 <assert.h>: Diagnostics
- 2 <avr/boot.h>: Bootloader Support Utilities
- 2 <avr/cpufunc.h>: Special AVR CPU functions
- 2 <avr/eeprom.h>: EEPROM handling
- 2 <avr/fuse.h>: Fuse Support
- 2 <avr/interrupt.h>: Interrupts
- 2 <avr/io.h>: AVR device-specific IO definitions
- 2 <avr/lock.h>: Lockbit Support
- 2 <avr/pgmspace.h>: Program Space Utilities
- 2 <avr/power.h>: Power Reduction Management
- 2 <avr/sfr_defs.h>: Special function registers
- 2 <avr/signature.h>: Signature Support
- 2 <avr/sleep.h>: Power Management and Sleep Modes
- 2 <avr/version.h>: avr-libc version macros
- 2 <avr/wdt.h>: Watchdog timer handling
- 2 <compat/deprecated.h>: Deprecated items
- 2 <compat/ina90.h>: Compatibility with IAR EWB 3.x
- 2 <ctype.h>: Character Operations
- 2 <errno.h>: System Errors
- 2 <inttypes.h>: Integer Type conversions
- 2 <math.h>: Mathematics
- 2 <setjmp.h>: Non-local goto
- 2 <stdint.h>: Standard Integer Types
- 2 <stdio.h>: Standard IO facilities
- 2 <stdlib.h>: General utilities
- 2 <string.h>: Strings
  - 2.1 Defines
  - 2.2 Functions
    - 2.2.1 int ffs
      int ffs(int __val)
    - 2.2.2 int ffsl
      int ffsl(long __val)
    - 2.2.3 int ffsll
      int ffsll(long long __val)
    - 2.2.4 void * memccpy
      void * memccpy(void *, const void *, int, size_t)
    - 2.2.5 void * memchr
      void * memchr(const void *, int, size_t) __ATTR_PURE__
    - 2.2.6 int memcmp
      int memcmp(const void *, const void *, size_t) __ATTR_PURE__
    - 2.2.7 void * memcpy
      void * memcpy(void *, const void *, size_t)
    - 2.2.8 void * memmem
      void * memmem(const void *, size_t, const void *, size_t) __ATTR_PURE__
    - 2.2.9 void * memmove
      void * memmove(void *, const void *, size_t)
    - 2.2.10 void * memrchr
      void * memrchr(const void *, int, size_t) __ATTR_PURE__
    - 2.2.11 void * memset
      void * memset(void *, int, size_t)
    - 2.2.12 char * strcat
      char * strcat(char *, const char *)
    - 2.2.13 char * strchr
      char * strchr(const char *, int) __ATTR_PURE__
    - 2.2.14 char * strchrnul
      char * strchrnul(const char *, int) __ATTR_PURE__
    - 2.2.15 int strcmp
      int strcmp(const char *, const char *) __ATTR_PURE__
    - 2.2.16 char * strcpy
      char * strcpy(char *, const char *)
    - 2.2.17 int strcasecmp
      int strcasecmp(const char *, const char *) __ATTR_PURE__
    - 2.2.18 char * strcasestr
      char * strcasestr(const char *, const char *) __ATTR_PURE__
    - 2.2.19 size_t strcspn
      size_t strcspn(const char *__s, const char *__reject) __ATTR_PURE__
    - 2.2.20 char * strdup
      char * strdup(const char *s1)
    - 2.2.21 size_t strlcat
      size_t strlcat(char *, const char *, size_t)
    - 2.2.22 size_t strlcpy
      size_t strlcpy(char *, const char *, size_t)
    - 2.2.23 size_t strlen
      size_t strlen(const char *) __ATTR_PURE__
    - 2.2.24 char * strlwr
      char * strlwr(char *)
    - 2.2.25 char * strncat
      char * strncat(char *, const char *, size_t)
    - 2.2.26 int strncmp
      int strncmp(const char *, const char *, size_t) __ATTR_PURE__
    - 2.2.27 char * strncpy
      char * strncpy(char *, const char *, size_t)
    - 2.2.28 int strncasecmp
      int strncasecmp(const char *, const char *, size_t) __ATTR_PURE__
    - 2.2.29 size_t strnlen
      size_t strnlen(const char *, size_t) __ATTR_PURE__
    - 2.2.30 char * strpbrk
      char * strpbrk(const char *__s, const char *__accept) __ATTR_PURE__
    - 2.2.31 char * strrchr
      char * strrchr(const char *, int) __ATTR_PURE__
    - 2.2.32 char * strrev
      char * strrev(char *)
    - 2.2.33 char * strsep
      char * strsep(char **, const char *)
    - 2.2.34 size_t strspn
      size_t strspn(const char *__s, const char *__accept) __ATTR_PURE__
    - 2.2.35 char * strstr
      char * strstr(const char *, const char *) __ATTR_PURE__
    - 2.2.36 char * strtok
      char * strtok(char *, const char *)
    - 2.2.37 char * strtok_r
      char * strtok_r(char *, const char *, char **)
    - 2.2.38 char * strupr
      char * strupr(char *)
- 2 <time.h>: Time
- 2 <util/atomic.h> Atomically and Non-Atomically Executed Code Blocks
- 2 <util/crc16.h>: CRC Computations
- 2 <util/delay.h>: Convenience functions for busy-wait delay loops
- 2 <util/delay_basic.h>: Basic busy-wait delay loops
- 2 <util/parity.h>: Parity bit generation
- 2 <util/setbaud.h>: Helper macros for baud rate calculations
- 2 <util/twi.h>: TWI bit mask definitions
- 2.1 Structures
3 Example Projects
4 Files

2.2.1 int ffs

int ffs(int __val)

Remember:

The ffs() function returns the position of the first (least significant) bit set in the word val, or 0 if no bits are set. The least significant bit is position 1.

Note:

For expressions that are constant at compile time, consider using the _FFS macro instead.

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