fgets(), gets() - get a line from a stream
#include <stdio.h>
char * fgets (char *str, size_t size, FILE *stream)
char * gets (char *str)
The fgets(3) function reads at most one less than the
number of characters specified by size from the given
stream and stores them in the string str. Reading
stops when a newline character is found, at end-of-file or error.
The newline, if any, is retained. In any case a \0
character is appended to end the string.
The gets(3) function is equivalent to fgets(3) with an infinite size 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.
Because the gets(3) function is a security violation, this implementation warns the user by writing the string, warning: this program uses gets(), which is unsafe.\r\n to standard error. This warning can be disabled by setting the environment variable DISABLE_GETS_WARNING.
Upon successful completion, fgets(3) and gets(3) return a pointer to the string. If end-of-file or an error occurs before any characters are read, they return NULL. The fgets(3) and functions gets(3) do not distinguish between end-of-file and error, and callers must use feof(3) and ferror(3) to determine which occurred.
The function fgets(3) 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(3) may also fail and set errno for any of the errors specified for the routine getchar(3).
Since it is usually impossible to ensure that the next input line is less than some arbitrary length, and because overflowing the input buffer is almost invariably a security violation, programs should never use gets(3). The gets(3) function exists to conform to ANSI-C.
feof(3)
ferror(3)