unix - C - does read() add a '\0'? -

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does have to? i've been fuzzy on sort of stuff, if have like:

char buf[256]; read(fd, buf, 256);  write(fd2, buf, 256);

is there potential error here, other cases functions return -1?

if read 40 characters, put \0 after it? (and write recognize \0 , stop? also, if read 256 characters, there \0 after 256?

does read() add '\0'?

no, doesn't. reads.

from read()'s documentation:

the read() function shall attempt read nbyte bytes file associated open file descriptor, fildes, buffer pointed buf.

is there potential error here, other cases functions return -1?

read() might return 0 indicating end-of-file.

if reading (also socket descriptor) read() not reads bytes told do. in context not test outcome of read against -1, compare against number of bytes function told read.

a general note:

functions documented (at least proper implementations of c language). both assumptions (autonomously set 0-termination, detect latter) not documented.


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