GETLINE(3C) Standard C Library Functions GETLINE(3C)

NAME


getline, getdelim - read delimited input from streams

SYNOPSIS


#include <stdio.h>


ssize_t getline(char **restrict ptr, size_t *restrict cap,
FILE *restrict stream);


ssize_t getdelim(char **restrict ptr, size_t *restrict cap,
int delimiter, FILE *restrict stream);


DESCRIPTION


The getdelim() function reads bytes from the stream into the array
pointed to by ptr, until the delimiter byte or an end-of-file condition
is encountered. The getline() function is identical in behaviour, but
uses the newline character as the delimiter. The delimiter character is
included in the string (unless end-of-file was reached first) and the
string is terminated with a null byte.

The caller may pass a pre-allocated malloc(3C) buffer as *ptr, along with
the capacity of that buffer as *cap. It is also valid to pass NULL for
*ptr and 0 for *cap, at which point memory will be allocated
automatically. If the buffer provided is not large enough to hold the
string it will be expanded, as if via realloc(3C). The caller must
free(3C) the buffer when it is no longer required.


RETURN VALUES


If successful, getdelim() and getline() return the number of bytes
written into the buffer, excluding the terminating null byte. If an
error occurs, or if end-of-file is reached prior to reading any bytes,
the value -1 is returned and errno is set to indicate the error.


ERRORS


The getline() and getdelim() functions may fail due to the following
errors:


EINVAL
Either ptr or cap are NULL, or the delimiter is not a valid
character.


EOVERFLOW
More than SSIZE_MAX characters were read from the stream
without encountering the delimiter.


The getline() and getdelim() functions may also fail and set errno for
any of the errors specified for the library routines realloc(3C) or
fgetc(3C).


EXAMPLES


Example 1: Read a line from stdin.




The following example uses getline to read a line from stdin.


#include <stdio.h>
...
char *ptr = NULL;
size_t cap = 0;

if (getline(&ptr, &cap, stdin) == -1) {
perror("getline");
exit(1);
}
fprintf(stdout, "input line: %s", ptr);

free(ptr);


ATTRIBUTES



+--------------------+-----------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+--------------------+-----------------+
|Interface Stability | Committed |
+--------------------+-----------------+
|MT-Level | MT-Safe |
+--------------------+-----------------+

SEE ALSO


fgetc(3C), fgets(3C), free(3C), malloc(3C), realloc(3C), attributes(7)

illumos April 9, 2016 GETLINE(3C)