FGETLN(3) | Library Functions Manual | FGETLN(3) |
fgetln
—
#include <stdio.h>
char *
fgetln
(FILE
* restrict stream, size_t
* restrict len);
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.)
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.
EBADF
]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).
fgetln
() function first appeared in
4.4BSD.
char *buf, *lbuf; size_t len; while ((lbuf = buf = fgetln(fp, &len)) != NULL) { if (len > 0 && buf[len - 1] == '\n') buf[len - 1] = '\0'; else if ((lbuf = strndup(buf, len + 1)) == NULL) err(1, NULL); printf("%s\n", lbuf); if (lbuf != buf) free(lbuf); }
July 4, 2018 | NetBSD 9.2 |