NAME | SYNOPSIS | DESCRIPTION | ATTRIBUTES | CONFORMING TO | SEE ALSO | COLOPHON |
UNLOCKED_STDIO(3) Linux Programmer's Manual UNLOCKED_STDIO(3)
getc_unlocked, getchar_unlocked, putc_unlocked, putchar_unlocked - nonlocking stdio functions
#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, size_t size, size_t n, FILE *stream); size_t fwrite_unlocked(const void *ptr, size_t size, size_t n, FILE *stream); char *fgets_unlocked(char *s, int n, FILE *stream); int fputs_unlocked(const char *s, FILE *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, int n, FILE *stream); int fputws_unlocked(const wchar_t *ws, FILE *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 versions <= 2.23: */ _POSIX_C_SOURCE || /* Glibc versions <= 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 versions <= 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
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).
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() │ │ │ └─────────────────────┴───────────────┴───────────────────────┘
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.
flockfile(3), stdio(3)
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2017-07-13 UNLOCKED_STDIO(3)
Pages that refer to this page: ferror(3), fflush(3), fgetc(3), fgetwc(3), fgetws(3), flockfile(3), fputwc(3), fputws(3), fread(3), gets(3), getwchar(3), puts(3), putwchar(3), stdio(3)