1FGETLN(3bsd) LOCAL FGETLN(3bsd)
2
4 fgetln — get a line from a stream
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7 Utility functions from BSD systems (libbsd, -lbsd)
8
10 #include <stdio.h>
11 (See libbsd(7) for include usage.)
12 char *
14 fgetln(FILE *stream, size_t *len);
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17 The fgetln() function returns a pointer to the next line from the stream
18 referenced by stream. This line is not a C string as it does not end
19 with a terminating NUL character. The length of the line, including the
20 final newline, is stored in the memory location to which len points and
21 is guaranteed to be greater than 0 upon successful completion. (Note,
22 however, that if the line is the last in a file that does not end in a
23 newline, the returned text will not contain a newline.)
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26 Upon successful completion a pointer is returned; this pointer becomes
27 invalid after the next I/O operation on stream (whether successful or
28 not) or as soon as the stream is closed. Otherwise, NULL is returned.
29 The fgetln() function does not distinguish between end-of-file and error;
30 the routines feof(3) and ferror(3) must be used to determine which
31 occurred. If an error occurs, the global variable errno is set to indi‐
32 cate the error. The end-of-file condition is remembered, even on a ter‐
33 minal, and all subsequent attempts to read will return NULL until the
34 condition is cleared with clearerr(3).
35 The text to which the returned pointer points may be modified, provided
37 that no changes are made beyond the returned size. These changes are
38 lost as soon as the pointer becomes invalid.
39
41 [EBADF] The argument stream is not a stream open for reading.
42 The fgetln() function may also fail and set errno for any of the errors
44 specified for the routines fflush(3), malloc(3), read(2), stat(2), or
45 realloc(3).
46
48 ferror(3), fgets(3), fgetwln(3bsd), fopen(3), putc(3)
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51 The fgetln() function first appeared in 4.4BSD.
52BSD April 19, 1994 BSD