NAME

       getc_unlocked,   getchar_unlocked,  putc_unlocked,  putchar_unlocked  -  nonlocking  stdio
       functions

LIBRARY

       Standard C library (libc, -lc)

SYNOPSIS

       #include <stdio.h>

       int getc_unlocked(FILE *stream);
       int getchar_unlocked(void);
       int putc_unlocked(int c, FILE *stream);
       int putchar_unlocked(int c);

       void clearerr_unlocked(FILE *stream);
       int feof_unlocked(FILE *stream);
       int ferror_unlocked(FILE *stream);
       int fileno_unlocked(FILE *stream);
       int fflush_unlocked(FILE *stream);

       int fgetc_unlocked(FILE *stream);
       int fputc_unlocked(int c, FILE *stream);

       size_t fread_unlocked(void ptr[restrict .size * .n],
                             size_t size, size_t n,
                             FILE *restrict stream);
       size_t fwrite_unlocked(const void ptr[restrict .size * .n],
                             size_t size, size_t n,
                             FILE *restrict stream);

       char *fgets_unlocked(char s[restrict .n], int n, FILE *restrict stream);
       int fputs_unlocked(const char *restrict s, FILE *restrict stream);

       #include <wchar.h>

       wint_t getwc_unlocked(FILE *stream);
       wint_t getwchar_unlocked(void);
       wint_t fgetwc_unlocked(FILE *stream);

       wint_t fputwc_unlocked(wchar_t wc, FILE *stream);
       wint_t putwc_unlocked(wchar_t wc, FILE *stream);
       wint_t putwchar_unlocked(wchar_t wc);

       wchar_t *fgetws_unlocked(wchar_t ws[restrict .n], int n,
                             FILE *restrict stream);
       int fputws_unlocked(const wchar_t *restrict ws,
                             FILE *restrict stream);

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       getc_unlocked(), getchar_unlocked(), putc_unlocked(), putchar_unlocked():
           /* glibc >= 2.24: */ _POSIX_C_SOURCE >= 199309L
               || /* glibc <= 2.23: */ _POSIX_C_SOURCE
               || /* glibc <= 2.19: */ _SVID_SOURCE || _BSD_SOURCE

       clearerr_unlocked(), feof_unlocked(), ferror_unlocked(), fileno_unlocked(),
       fflush_unlocked(), fgetc_unlocked(), fputc_unlocked(), fread_unlocked(),
       fwrite_unlocked():
           /* glibc >= 2.19: */ _DEFAULT_SOURCE
               || /* glibc <= 2.19: */ _SVID_SOURCE || _BSD_SOURCE

       fgets_unlocked(), fputs_unlocked(), getwc_unlocked(), getwchar_unlocked(),
       fgetwc_unlocked(), fputwc_unlocked(), putwchar_unlocked(), fgetws_unlocked(),
       fputws_unlocked():
           _GNU_SOURCE

DESCRIPTION

       Each of these functions has the same behavior as its counterpart without  the  "_unlocked"
       suffix,  except that they do not use locking (they do not set locks themselves, and do not
       test for the  presence  of  locks  set  by  others)  and  hence  are  thread-unsafe.   See
       flockfile(3).

ATTRIBUTES

       For an explanation of the terms used in this section, see attributes(7).

       ┌─────────────────────┬───────────────┬───────────────────────────────────────────────────┐
       │Interface            │ Attribute     │ Value                                             │
       ├─────────────────────┼───────────────┼───────────────────────────────────────────────────┤
       │getc_unlocked(),     │ Thread safety │ MT-Safe race:stream                               │
       │putc_unlocked(),     │               │                                                   │
       │clearerr_unlocked(), │               │                                                   │
       │fflush_unlocked(),   │               │                                                   │
       │fgetc_unlocked(),    │               │                                                   │
       │fputc_unlocked(),    │               │                                                   │
       │fread_unlocked(),    │               │                                                   │
       │fwrite_unlocked(),   │               │                                                   │
       │fgets_unlocked(),    │               │                                                   │
       │fputs_unlocked(),    │               │                                                   │
       │getwc_unlocked(),    │               │                                                   │
       │fgetwc_unlocked(),   │               │                                                   │
       │fputwc_unlocked(),   │               │                                                   │
       │putwc_unlocked(),    │               │                                                   │
       │fgetws_unlocked(),   │               │                                                   │
       │fputws_unlocked()    │               │                                                   │
       ├─────────────────────┼───────────────┼───────────────────────────────────────────────────┤
       │getchar_unlocked(),  │ Thread safety │ MT-Unsafe race:stdin                              │
       │getwchar_unlocked()  │               │                                                   │
       ├─────────────────────┼───────────────┼───────────────────────────────────────────────────┤
       │putchar_unlocked(),  │ Thread safety │ MT-Unsafe race:stdout                             │
       │putwchar_unlocked()  │               │                                                   │
       ├─────────────────────┼───────────────┼───────────────────────────────────────────────────┤
       │feof_unlocked(),     │ Thread safety │ MT-Safe                                           │
       │ferror_unlocked(),   │               │                                                   │
       │fileno_unlocked()    │               │                                                   │
       └─────────────────────┴───────────────┴───────────────────────────────────────────────────┘

STANDARDS

       The    four    functions     getc_unlocked(),     getchar_unlocked(),     putc_unlocked(),
       putchar_unlocked() are in POSIX.1-2001 and POSIX.1-2008.

       The  nonstandard  *_unlocked()  variants occur on a few UNIX systems, and are available in
       recent glibc.  They should probably not be used.

SEE ALSO

       flockfile(3), stdio(3)