gets函数

GETS(3)                    Linux Programmer’s Manual                   GETS(3)

NAME
       fgetc, fgets, getc, getchar, gets, ungetc - input of characters and strings

SYNOPSIS
       #include

       int fgetc(FILE *stream);

       char *fgets(char *s, int size, FILE *stream);

       int getc(FILE *stream);

       int getchar(void);

       char *gets(char *s);

       int ungetc(int c, FILE *stream);

DESCRIPTION
       fgetc() reads the next character from stream and returns it as an unsigned char cast to an int, or EOF
       on end of file or error.

       getc() is equivalent to fgetc() except that it may be implemented as a macro  which  evaluates  stream
       more than once.

       getchar() is equivalent to getc(stdin).

       gets()  reads  a line from stdin into the buffer pointed to by s until either a terminating newline or
       EOF, which it replaces with '\0'.  No check for buffer overrun is performed (see BUGS below).

       fgets() reads in at most one less than size characters from stream and stores  them  into  the  buffer
       pointed  to  by  s.  Reading stops after an EOF or a newline.  If a newline is read, it is stored into
       the buffer.  A '\0' is stored after the last character in the buffer.

       ungetc() pushes c back to stream, cast to unsigned char, where it is  available  for  subsequent  read
       operations.   Pushed-back  characters  will be returned in reverse order; only one pushback is guaran-
       teed.

       Calls to the functions described here can be mixed with each other and with calls to other input func-
       tions from the stdio library for the same input stream.

       For non-locking counterparts, see unlocked_stdio(3).

RETURN VALUE
       fgetc(),  getc()  and getchar() return the character read as an unsigned char cast to an int or EOF on
       end of file or error.

       gets() and fgets() return s on success, and NULL on error or when end of file occurs while no  charac-
       ters have been read.

       ungetc() returns c on success, or EOF on error.

CONFORMING TO
       C89, C99, POSIX.1-2001.  LSB deprecates gets().  POSIX.1-2008 removes the specification of gets().

BUGS
       Never use gets().  Because it is impossible to tell without knowing the data in advance how many char-
       acters gets() will read, and because gets() will continue to store characters  past  the  end  of  the
       buffer,  it  is extremely dangerous to use.  It has been used to break computer security.  Use fgets()
       instead.

       It is not advisable to mix calls to input functions from the stdio library  with  low-level  calls  to

      read(2)  for  the  file descriptor associated with the input stream; the results will be undefined and
       very probably not what you want.

SEE ALSO
       read(2),  write(2),  ferror(3),  fgetwc(3),  fgetws(3),  fopen(3),  fread(3),  fseek(3),   getline(3),
       getwchar(3), puts(3), scanf(3), ungetwc(3), unlocked_stdio(3)

COLOPHON
       This  page  is part of release 3.22 of the Linux man-pages project.  A description of the project, and
       information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.

gets的man手册