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FGETS(3)                                BSD Library Functions Manual                                FGETS(3)

NAME
     fgets, gets -- get a line from a stream

LIBRARY
     Standard C Library (libc, -lc)

SYNOPSIS
     #include <stdio.h>

     char *
     fgets(char *restrict s, int n, FILE *restrict stream);

     char *
     gets(char *s);

DESCRIPTION
     The fgets() function reads at most one less than the number of characters specified by n from the given
     stream and stores them in the string s.  Reading stops when a newline character is found, at end-of-file end-offile
     file or error.  The newline, if any, is retained.  If any characters are read and there is no error, a
     `\0' character is appended to end the string.

     The gets() function is equivalent to fgets() with an infinite n and a stream of stdin, except that the
     newline character (if any) is not stored in the string.  It is the caller's responsibility to ensure
     that the input line, if any, is sufficiently short to fit in the string.

RETURN VALUES
     Upon successful completion, fgets() and gets() return a pointer to the string.  If end-of-file occurs
     before any characters are read, they return NULL and the buffer contents remain unchanged.  If an error
     occurs, they return NULL and the buffer contents are indeterminate.  The fgets() and gets() functions
     do not distinguish between end-of-file and error; callers must use feof(3) and ferror(3) to determine
     which occurred.

ERRORS
     [EBADF]            The given stream is not a readable stream.

     The function fgets() may also fail and set errno for any of the errors specified for the routines
     fflush(3), fstat(2), read(2), or malloc(3).

     The function gets() may also fail and set errno for any of the errors specified for the routine
     getchar(3).

SECURITY CONSIDERATIONS
     The gets() function cannot be used securely.  Because of its lack of bounds checking, and the inability
     for the calling program to reliably determine the length of the next incoming line, the use of this
     function enables malicious users to arbitrarily change a running program's functionality through a
     buffer overflow attack.  It is strongly suggested that the fgets() function be used in all cases.  (See
     the FSA.)

SEE ALSO
     feof(3), ferror(3), fgetln(3), fgetws(3)

STANDARDS
     The functions fgets() and gets() conform to ISO/IEC 9899:1999 (``ISO C99'').

BSD                                             June 4, 1993                                             BSD