---
name: "fparseln"
section: "3"
platform: "linux"
package: "libbsd-dev"
version: "0.8.3-1"
release: "Debian 9 (Stretch)"
platforms: ["linux", "freebsd", "macos"]
url: "https://new.carta.tech/fparseln"
---

# fparseln(3)

return the next logical line from a stream

## NAME

**fparseln** – return the next logical line from a stream

## LIBRARY

library “libbsd”

## SYNOPSIS

**#include \<bsd/stdio.h\>**

*char \**\

**fparseln**(*FILE \*stream*, *size\_t \*len*, *size\_t \*lineno*, *const char delim\[3\]*, *int flags*);

## DESCRIPTION

The **fparseln**() function returns a pointer to the next logical line from the stream referenced by *stream*. This string is NUL terminated and it is dynamically allocated on each invocation. It is the responsibility of the caller to free the pointer.

By default, if a character is escaped, both it and the preceding escape character will be present in the returned string. Various *flags* alter this behaviour.

The meaning of the arguments is as follows:

- *stream*

  The stream to read from.

- *len*

  If not NULL, the length of the string is stored in the memory location to which it points.

- *lineno*

  If not NULL, the value of the memory location to which is pointed to, is incremented by the number of lines actually read from the file.

- *delim*

  Contains the escape, continuation, and comment characters. If a character is NUL then processing for that character is disabled. If NULL, all characters default to values specified below. The contents of *delim* is as follows:

  - *delim\[0\]*

    The escape character, which defaults to **\\**, is used to remove any special meaning from the next character.

  - *delim\[1\]*

    The continuation character, which defaults to **\\**, is used to indicate that the next line should be concatenated with the current one if this character is the last character on the current line and is not escaped.

  - *delim\[2\]*

    The comment character, which defaults to **#**, if not escaped indicates the beginning of a comment that extends until the end of the current line.

- *flags*

  If non-zero, alter the operation of **fparseln**(). The various flags, which may be *or*-ed together, are:

  - FPARSELN\_UNESCCOMM

    Remove escape preceding an escaped comment.

  - FPARSELN\_UNESCCONT

    Remove escape preceding an escaped continuation.

  - FPARSELN\_UNESCESC

    Remove escape preceding an escaped escape.

  - FPARSELN\_UNESCREST

    Remove escape preceding any other character.

  - FPARSELN\_UNESCALL

    All of the above.

## RETURN VALUES

Upon successful completion a pointer to the parsed line is returned; otherwise, NULL is returned.

The **fparseln**() function uses internally [getline(3)](/getline/3.md), so all error conditions that apply to [getline(3)](/getline/3.md), apply to **fparseln**(). In addition **fparseln**() may set *errno* to \[ENOMEM\] and return NULL if it runs out of memory.

## SEE ALSO

[getline(3)](/getline/3.md)

## HISTORY

The **fparseln**() function first appeared in NetBSD 1.4.