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
  - 2.1 Typedefs
  - 2.2 Functions
    - 2.2.1 int fclose
      int fclose(FILE *__stream)
    - 2.2.2 int vfprintf
      int vfprintf(FILE *__stream, const char *__fmt, va_list __ap)
    - 2.2.3 int vfprintf_P
      int vfprintf_P(FILE *__stream, const char *__fmt, va_list __ap)
    - 2.2.4 int fputc
      int fputc(int __c, FILE *__stream)
    - 2.2.5 int printf
      int printf(const char *__fmt,...)
    - 2.2.6 int printf_P
      int printf_P(const char *__fmt,...)
    - 2.2.7 int vprintf
      int vprintf(const char *__fmt, va_list __ap)
    - 2.2.8 int sprintf
      int sprintf(char *__s, const char *__fmt,...)
    - 2.2.9 int sprintf_P
      int sprintf_P(char *__s, const char *__fmt,...)
    - 2.2.10 int snprintf
      int snprintf(char *__s, size_t __n, const char *__fmt,...)
    - 2.2.11 int snprintf_P
      int snprintf_P(char *__s, size_t __n, const char *__fmt,...)
    - 2.2.12 int vsprintf
      int vsprintf(char *__s, const char *__fmt, va_list ap)
    - 2.2.13 int vsprintf_P
      int vsprintf_P(char *__s, const char *__fmt, va_list ap)
    - 2.2.14 int vsnprintf
      int vsnprintf(char *__s, size_t __n, const char *__fmt, va_list ap)
    - 2.2.15 int vsnprintf_P
      int vsnprintf_P(char *__s, size_t __n, const char *__fmt, va_list ap)
    - 2.2.16 int fprintf
      int fprintf(FILE *__stream, const char *__fmt,...)
    - 2.2.17 int fprintf_P
      int fprintf_P(FILE *__stream, const char *__fmt,...)
    - 2.2.18 int fputs
      int fputs(const char *__str, FILE *__stream)
    - 2.2.19 int fputs_P
      int fputs_P(const char *__str, FILE *__stream)
    - 2.2.20 int puts
      int puts(const char *__str)
    - 2.2.21 int puts_P
      int puts_P(const char *__str)
    - 2.2.22 size_t fwrite
      size_t fwrite(const void *__ptr, size_t __size, size_t __nmemb, FILE *__stream)
    - 2.2.23 int fgetc
      int fgetc(FILE *__stream)
    - 2.2.24 int ungetc
      int ungetc(int __c, FILE *__stream)
    - 2.2.25 char* fgets
      char* fgets(char *__str, int __size, FILE *__stream)
    - 2.2.26 char* gets
      char* gets(char *__str)
    - 2.2.27 size_t fread
      size_t fread(void *__ptr, size_t __size, size_t __nmemb, FILE *__stream)
    - 2.2.28 void clearerr
      void clearerr(FILE *__stream)
    - 2.2.29 int feof
      int feof(FILE *__stream)
    - 2.2.30 int ferror
      int ferror(FILE *__stream)
    - 2.2.31 int vfscanf
      int vfscanf(FILE *__stream, const char *__fmt, va_list __ap)
    - 2.2.32 int vfscanf_P
      int vfscanf_P(FILE *__stream, const char *__fmt, va_list __ap)
    - 2.2.33 int fscanf
      int fscanf(FILE *__stream, const char *__fmt,...)
    - 2.2.34 int fscanf_P
      int fscanf_P(FILE *__stream, const char *__fmt,...)
    - 2.2.35 int scanf
      int scanf(const char *__fmt,...)
    - 2.2.36 int scanf_P
      int scanf_P(const char *__fmt,...)
    - 2.2.37 int vscanf
      int vscanf(const char *__fmt, va_list __ap)
    - 2.2.38 int sscanf
      int sscanf(const char *__buf, const char *__fmt,...)
    - 2.2.39 int sscanf_P
      int sscanf_P(const char *__buf, const char *__fmt,...)
    - 2.2.40 int fflush
      int fflush(FILE *stream)
    - 2.2.41 FILE* fdevopen
      FILE* fdevopen(int(*put)(char, FILE *), int(*get)(FILE *))
  - 2.3 Defines
- 2 <stdlib.h>: General utilities
- 2 <string.h>: Strings
- 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

2.2.24 int ungetc

int ungetc(int __c, FILE *__stream)

The ungetc() function pushes the character c (converted to an unsigned char) back onto the input stream pointed to by stream. The pushed-back character will be returned by a subsequent read on the stream.

Currently, only a single character can be pushed back onto the stream.

The ungetc() function returns the character pushed back after the conversion, or EOF if the operation fails. If the value of the argument c character equals EOF, the operation will fail and the stream will remain unchanged.

The online versions of the documents are provided as a courtesy. Verify all content and data in the device’s PDF documentation found on the device product page.