read_n_chars
read_n_chars — reads and stores characters.
read_n_chars (file, nchars)
fileA file pointer to a previously opened file. This may be either a file in the file system, or a string opened for read and write.
ncharsThe number of characters to read.
A buffer containing the characters read. The length of the return buffer
is equal to the number of characters actually read. This function returns
nil if no characters
could be read.
This function reads the given number of characters from the file, without any form of translation, and builds a new buffer object in which to store them. If this function reaches the end of the file before all characters are read, then the buffer will be shorter than the requested number of characters.
An input file contains the following:
To be or not to be, that is the question.
Successive calls to read_n_chars will produce:
Gamma>ft = open ("myreadnfile.dat", "r");#<File:"myreadnfile.dat">Gamma>read_n_chars(ft,15);#{To be or not to}Gamma>read_n_chars(ft,18);#{ be, that is the q}Gamma>read_n_chars(ft,18);#{uestion.}Gamma>read_n_chars(ft,18);nilGamma>