CODEWITHSUNDEEP
clinuxgetline
xificurC
xificurC

Reputation: 1178

how does getline read only up to a newline without seeking?

I'm imagining reading byte by byte would be very inefficient, but reading in bulks would almost always read more than needed, requiring to store the rest of the read input in a global context for all subsequent read operations to find. What am I missing?

Upvotes: 1

Views: 140

Answers (2)

Serge Ballesta
Serge Ballesta

Reputation: 148870

That is what buffered io is for. Long story short, the C library reads a full buffer the size of which is implementation dependant but is rather large, and then the getline function looks for the first newline in that memory buffer, leaving the pointer positioned for next access.

Upvotes: 2

unwind
unwind

Reputation: 399703

The prototype is:

ssize_t getline(char **lineptr, size_t *n, FILE *stream);

So it's clearly using FILE, which is already buffered. So reading character-by-character is not inefficient at all.

Upvotes: 3

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