NAME¶
fgetln
—
get a line from a stream
LIBRARY¶
library “libbsd”
SYNOPSIS¶
#include
<bsd/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 and is guaranteed to be
greater than 0 upon successful completion. (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.
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),
putc(3)
HISTORY¶
The
fgetln
() function first appeared in
4.4BSD.