Manpage of GETLINE

GETLINE

Section: Linux Programmer's Manual (3)
Updated: 2016-03-15
Index
 

NAME

getline, getdelim - delimited string input  

SYNOPSIS

#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);

Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

getline(), getdelim():

Since glibc 2.10:
_POSIX_C_SOURCE >= 200809L
Before glibc 2.10:
_GNU_SOURCE
 

DESCRIPTION

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 *lineptris set to NULL and *nis set 0 before the call, then getline() will allocate a buffer for storing the line. This buffer should be freed by the user program even if getline() failed.

Alternatively, before calling getline(), *lineptrcan contain a pointer to a malloc(3)-allocated buffer *nbytes in size. If the buffer is not large enough to hold the line, getline() resizes it with realloc(3), updating *lineptrand *nas necessary.

In either case, on a successful call, *lineptrand *nwill be updated to reflect the buffer address and allocated size respectively.

getdelim() works like getline(), except that a line delimiter other than newline can be specified as the delimiterargument. As with getline(), a delimiter character is not added if one was not present in the input before end of file was reached.  

RETURN VALUE

On success, getline() and getdelim() return the number of characters read, including the delimiter character, but not including the terminating null byte (aq\0aq). 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). In the event of an error, errnois set to indicate the cause.  

ERRORS

EINVAL
Bad arguments (nor lineptris NULL, or streamis not valid).
 

ATTRIBUTES

For an explanation of the terms used in this section, see attributes(7).
InterfaceAttributeValue
getline(), getdelim() Thread safetyMT-Safe

 

CONFORMING TO

Both getline() and getdelim() were originally GNU extensions. They were standardized in POSIX.1-2008.  

EXAMPLE

#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>

int
main(void)
{
    FILE *stream;
    char *line = NULL;
    size_t len = 0;
    ssize_t read;

    stream = fopen("/etc/motd", "r");
    if (stream == NULL)
        exit(EXIT_FAILURE);

    while ((read = getline(&line, &len, stream)) != -1) {
        printf("Retrieved line of length %zu :\n", read);
        printf("%s", line);
    }

    free(line);
    fclose(stream);
    exit(EXIT_SUCCESS);
}
 

SEE ALSO

read(2), fgets(3), fopen(3), fread(3), scanf(3)


 

Index

NAME
SYNOPSIS
DESCRIPTION
RETURN VALUE
ERRORS
ATTRIBUTES
CONFORMING TO
EXAMPLE
SEE ALSO

This document was created by man2html, using the manual pages.
Time: 22:27:45 GMT, June 20, 2016