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Copyright (c) 2013, Joyent, Inc. All rights reserved.

GETLINE 3C "April 9, 2016"
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)