fgetline - get a line from a stream

#include <stdio.h>

char *fgetline(stream, len)
FILE *stream;
size_t *len;

The fgetline function returns a pointer to the next line from the
stream referenced by stream. The newline character at the end of
the line is replaced by a NUL.

If len is non-NULL, the length of the line, not counting the
terminating NUL, is stored in the memory location it references.

Upon successful completion a pointer is returned; this pointer
becomes invalid after the next I/O operation on stream (whether
successful or not) or as soon as the stream is closed. Otherwise,
NULL is returned. The fgetline function does not distinguish
between end-of-file and error; the routines feof(3) and ferror(3)
must be used to determine which occurred. If an error occurrs, the
global variable errno is set to indicate the error. The end-of-
file condition is remembered, even on a terminal, and all
subsequent attempts to read will return NULL until the condition is
cleared with clearerr(3).

The text to which the returned pointer points may be modified,
provided that no changes are made beyond the terminating NUL.
These changes are lost as soon as the pointer becomes invalid.

The argument stream is not a stream open for reading.

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

ferror(3), fgets(3), fopen(3), putc(3)

The fgetline function is currently under development.

It is not possible to tell whether the final line of an input file
was terminated with a newline.