method

read

v1_8_7_330 - Show latest stable - 0 notes - Class: IO

read(...) public

Opens the file, optionally seeks to the given offset, then returns length bytes (defaulting to the rest of the file). read ensures the file is closed before returning.

IO.read("testfile")           #=> "This is line one\nThis is line two\nThis is line three\nAnd so on...\n"
IO.read("testfile", 20)       #=> "This is line one\nThi"
IO.read("testfile", 20, 10)   #=> "ne one\nThis is line "

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/*
 *  call-seq:
 *     IO.read(name, [length [, offset]] )   => string
 *  
 *  Opens the file, optionally seeks to the given offset, then returns
 *  <i>length</i> bytes (defaulting to the rest of the file).
 *  <code>read</code> ensures the file is closed before returning.
 *     
 *     IO.read("testfile")           #=> "This is line one\nThis is line two\nThis is line three\nAnd so on...\n"
 *     IO.read("testfile", 20)       #=> "This is line one\nThi"
 *     IO.read("testfile", 20, 10)   #=> "ne one\nThis is line "
 */

static VALUE
rb_io_s_read(argc, argv, io)
    int argc;
    VALUE *argv;
    VALUE io;
{
    VALUE fname, offset;
    struct foreach_arg arg;

    rb_scan_args(argc, argv, "12", &fname, &arg.sep, &offset);
    SafeStringValue(fname);

    arg.argc = argc ? 1 : 0;
    arg.io = rb_io_open(StringValueCStr(fname), "r");
    if (NIL_P(arg.io)) return Qnil;
    if (!NIL_P(offset)) {
        struct seek_arg sarg;
        int state = 0;
        sarg.io = arg.io;
        sarg.offset = offset;
        sarg.mode = SEEK_SET;
        rb_protect((VALUE (*)(VALUE))seek_before_read, (VALUE)&sarg, &state);
        if (state) {
            rb_io_close(arg.io);
            rb_jump_tag(state);
        }
    }
    return rb_ensure(io_s_read, (VALUE)&arg, rb_io_close, arg.io);
}

read

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