getline, getdelim — delimited string input
#define _GNU_SOURCE #include <stdio.h>
ssize_t getline( |
char ** | lineptr, |
size_t * | n, | |
FILE * | stream) ; |
ssize_t getdelim( |
char ** | lineptr, |
size_t * | n, | |
int | delim, | |
FILE * | stream) ; |
getline
() reads an entire
line from stream
,
storing the address of the buffer containing the text into
*lineptr
. The
buffer is null-terminated and includes the newline character,
if one was found.
If *lineptr
is
NULL, then getline
() will
allocate a buffer for storing the line, which should be freed
by the user program. Alternatively, before calling
getline
(), *lineptr
can contain a
pointer to a malloc(3)\-allocated buffer
*n
bytes in size.
If the buffer is not large enough to hold the line,
getline
() resizes it with
realloc(3), updating
*lineptr
and
*n
as necessary. In
either case, on a successful call, *lineptr
and *n
will be updated to reflect
the buffer address and allocated size respectively.
getdelim
() works like
getline
(), except a line
delimiter other than newline can be specified as the
delimiter
argument.
As with getline
(), a delimiter
character is not added if one was not present in the input
before end of file was reached.
On success, getline
() and
getdelim
() return the number of
characters read, including the delimiter character, but not
including the terminating null byte. This value can be used
to handle embedded null bytes in the line read.
Both functions return −1 on failure to read a line (including end of file condition).
Both getline
() and
getdelim
() are GNU extensions.
They are available since libc 4.6.27.
#define _GNU_SOURCE #include <stdio.h> #include <stdlib.h> int main(void) { FILE * fp; char * line = NULL; size_t len = 0; ssize_t read; fp = fopen("/etc/motd", "r"); if (fp == NULL) exit(EXIT_FAILURE); while ((read = getline(&line, &len, fp)) != −1) { printf("Retrieved line of length %zu :\n", read); printf("%s", line); } if (line) free(line); return EXIT_SUCCESS; }
read(2), fgets(3), fopen(3), fread(3), gets(3), scanf(3), feature_test_macros(7)
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