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| author | Alejandro Colomar <alx@kernel.org> | 2024-04-26 15:06:49 +0200 |
|---|---|---|
| committer | Alejandro Colomar <alx@kernel.org> | 2024-05-02 01:24:19 +0200 |
| commit | dcde2f70372b49ec43efc5db864c9ff585d0a2dd (patch) | |
| tree | 78b9b7425130e4a5858e4c01a524d802423879ed /man/man3/scanf.3 | |
| parent | 12aca537ce78a41bbcdaf485209691e10f8002d7 (diff) | |
| download | man-pages-dcde2f70372b49ec43efc5db864c9ff585d0a2dd.tar.gz | |
man/, share/mk/: Move man*/ to man/
This is a scripted change:
$ mkdir man/;
$ mv man* man/;
$ ln -st . man/man*;
$ find share/mk/ -type f \
| xargs grep -l '^MANDIR *:=' \
| xargs sed -i '/^MANDIR *:=/s,$,/man,';
$ find share/mk/dist/ -type f \
| xargs grep -l man \
| xargs sed -i 's,man%,man/%,g';
Link: <https://lore.kernel.org/linux-man/YxcV4h+Xn7cd6+q2@pevik/T/>
Cc: Petr Vorel <pvorel@suse.cz>
Cc: Jakub Wilk <jwilk@jwilk.net>
Cc: Stefan Puiu <stefan.puiu@gmail.com>
Signed-off-by: Alejandro Colomar <alx@kernel.org>
Diffstat (limited to 'man/man3/scanf.3')
| -rw-r--r-- | man/man3/scanf.3 | 159 |
1 files changed, 159 insertions, 0 deletions
diff --git a/man/man3/scanf.3 b/man/man3/scanf.3 new file mode 100644 index 0000000000..be335a5974 --- /dev/null +++ b/man/man3/scanf.3 @@ -0,0 +1,159 @@ +'\" t +.\" Copyright 2022 Alejandro Colomar <alx@kernel.org> +.\" SPDX-License-Identifier: Linux-man-pages-copyleft +.\" +.TH scanf 3 (date) "Linux man-pages (unreleased)" +.SH NAME +scanf, fscanf, vscanf, vfscanf \- input FILE format conversion +.SH LIBRARY +Standard C library +.RI ( libc ", " \-lc ) +.SH SYNOPSIS +.nf +.B #include <stdio.h> +.P +.BI "int scanf(const char *restrict " format ", ...);" +.BI "int fscanf(FILE *restrict " stream , +.BI " const char *restrict " format ", ...);" +.P +.B #include <stdarg.h> +.P +.BI "int vscanf(const char *restrict " format ", va_list " ap ); +.BI "int vfscanf(FILE *restrict " stream , +.BI " const char *restrict " format ", va_list " ap ); +.fi +.P +.RS -4 +Feature Test Macro Requirements for glibc (see +.BR feature_test_macros (7)): +.RE +.P +.BR vscanf (), +.BR vfscanf (): +.nf + _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L +.fi +.SH DESCRIPTION +The +.BR scanf () +family of functions scans formatted input like +.BR sscanf (3), +but read from a +.IR FILE . +It is very difficult to use these functions correctly, +and it is preferable to read entire lines with +.BR fgets (3) +or +.BR getline (3) +and parse them later with +.BR sscanf (3) +or more specialized functions such as +.BR strtol (3). +.P +The +.BR scanf () +function reads input from the standard input stream +.I stdin +and +.BR fscanf () +reads input from the stream pointer +.IR stream . +.P +The +.BR vfscanf () +function is analogous to +.BR vfprintf (3) +and reads input from the stream pointer +.I stream +using a variable argument list of pointers (see +.BR stdarg (3). +The +.BR vscanf () +function is analogous to +.BR vprintf (3) +and reads from the standard input. +.SH RETURN VALUE +On success, these functions return the number of input items +successfully matched and assigned; +this can be fewer than provided for, +or even zero, in the event of an early matching failure. +.P +The value +.B EOF +is returned if the end of input is reached before either the first +successful conversion or a matching failure occurs. +.B EOF +is also returned if a read error occurs, +in which case the error indicator for the stream (see +.BR ferror (3)) +is set, and +.I errno +is set to indicate the error. +.SH ERRORS +.TP +.B EAGAIN +The file descriptor underlying +.I stream +is marked nonblocking, and the read operation would block. +.TP +.B EBADF +The file descriptor underlying +.I stream +is invalid, or not open for reading. +.TP +.B EILSEQ +Input byte sequence does not form a valid character. +.TP +.B EINTR +The read operation was interrupted by a signal; see +.BR signal (7). +.TP +.B EINVAL +Not enough arguments; or +.I format +is NULL. +.TP +.B ENOMEM +Out of memory. +.SH ATTRIBUTES +For an explanation of the terms used in this section, see +.BR attributes (7). +.TS +allbox; +lbx lb lb +l l l. +Interface Attribute Value +T{ +.na +.nh +.BR scanf (), +.BR fscanf (), +.BR vscanf (), +.BR vfscanf () +T} Thread safety MT-Safe locale +.TE +.SH STANDARDS +C11, POSIX.1-2008. +.SH HISTORY +C99, POSIX.1-2001. +.SH CAVEATS +These functions make it difficult to +distinguish newlines from other white space, +This is especially problematic with line-buffered input, +like the standard input stream. +.P +These functions can't report errors after the last +non-suppressed conversion specification. +.SH BUGS +It is impossible to accurately know +how many characters these functions have consumed from the input stream, +since they only report the number of successful conversions. +For example, +if the input is "123\en\ a", +.I scanf(\[dq]%d\ %d\[dq], &a, &b) +will consume the digits, the newline, and the space, but not the letter a. +This makes it difficult to recover from invalid input. +.SH SEE ALSO +.BR fgets (3), +.BR getline (3), +.BR sscanf (3) |