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5 .\" Chris Torek and the American National Standards Committee X3,
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32 .\" @(#)fgets.3 8.1 (Berkeley) 6/4/93
42 .Nd get a line from a stream
48 .Fn fgets "char * restrict str" "int size" "FILE * restrict stream"
50 .Fn gets_s "char *str" "rsize_t size"
57 reads at most one less than the number of characters specified by
61 and stores them in the string
63 Reading stops when a newline character is found,
64 at end-of-file or error.
65 The newline, if any, is retained.
66 If any characters are read and there is no error, a
68 character is appended to end the string.
79 except that the newline character (if any) is not stored in the string.
92 except that the newline character (if any) is not stored in the string.
93 It is the caller's responsibility to ensure that the input line,
94 if any, is sufficiently short to fit in the string.
96 Upon successful completion,
102 a pointer to the string.
103 If end-of-file occurs before any characters are read,
106 and the buffer contents remain unchanged.
110 and the buffer contents are indeterminate.
117 do not distinguish between end-of-file and error, and callers must use
121 to determine which occurred.
127 is not a readable stream.
132 may also fail and set
134 for any of the errors specified for the routines
143 may also fail and set
145 for any of the errors specified for the routine
165 has been removed from
167 .Sh SECURITY CONSIDERATIONS
170 function cannot be used securely.
171 Because of its lack of bounds checking,
172 and the inability for the calling program
173 to reliably determine the length of the next incoming line,
174 the use of this function enables malicious users
175 to arbitrarily change a running program's functionality through
176 a buffer overflow attack.
177 It is strongly suggested that the
179 function be used in all cases.