fparseln (3) - Linux Manuals

fparseln: return the next logical line from a stream


fparseln - return the next logical line from a stream


Lb libbsd


In bsd/stdio.h Ft char * Fo fparseln Fa FILE *stream size_t *len size_t *lineno Fa const char delim[3] int flags Fc


The Fn fparseln function returns a pointer to the next logical line from the stream referenced by Fa 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 Fa flags alter this behaviour.

The meaning of the arguments is as follows:

Fa stream
The stream to read from.
Fa len
If not NULL the length of the string is stored in the memory location to which it points.
Fa 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.
Fa 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 Fa delim is as follows:

Fa delim[0]
The escape character, which defaults to \ is used to remove any special meaning from the next character.
Fa 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.
Fa 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.

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

Remove escape preceding an escaped comment.
Remove escape preceding an escaped continuation.
Remove escape preceding an escaped escape.
Remove escape preceding any other character.
All of the above.


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

The Fn fparseln function uses internally fgetln(3), so all error conditions that apply to fgetln(3), apply to Fn fparseln . In addition Fn fparseln may set errno to Bq Er ENOMEM and return NULL if it runs out of memory.


The Fn fparseln function first appeared in Nx 1.4 .