неблокирующие функции stdio  (nonlocking stdio functions)
  
Имя (Name)
getc_unlocked, getchar_unlocked, putc_unlocked, putchar_unlocked
       - nonlocking stdio functions
Синопсис (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 *restrict ptr, size_t size, size_t n,
                             FILE *restrict stream);
       size_t fwrite_unlocked(const void *restrict ptr, size_t size, size_t n,
                             FILE *restrict stream);
       char *fgets_unlocked(char *restrict s, 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 *restrict ws, 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():
           /* Since 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 since 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
Описание (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).
Атрибуты (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()    │               │                          │
       └─────────────────────┴───────────────┴──────────────────────────┘
Стандарты (Conforming to)
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.
Смотри также (See also)
flockfile(3), stdio(3)