NAME
fgetln —
get a line from a stream
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include
<stdio.h>
char *
fgetln(FILE
*stream, size_t
*len);
DESCRIPTION
The
fgetln()
function returns a pointer to the next line from the stream referenced by
stream. This line is
not a C
string as it does not end with a terminating NUL
character. The length of the line, including the final newline, is stored in
the memory location to which len points. (Note,
however, that if the line is the last in a file that does not end in a
newline, the returned text will not contain a newline.)
RETURN VALUES
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
fgetln() 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 occurs, 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 returned size. These changes are lost as soon as the pointer becomes invalid.
ERRORS
- [
EBADF] - The argument stream is not a stream open for reading.
- [
ENOMEM] - The internal line buffer could not be expanded due to lack of available memory, or because it would need to expand beyond INT_MAX in size.
The fgetln() 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).
SEE ALSO
ferror(3), fgets(3), fgetwln(3), fopen(3), getline(3), putc(3)
HISTORY
The fgetln() function first appeared in
4.4BSD.