FIFOs implementation
c, fifo, linux
Solution
A separator is one way to go about it, and this will work fine, as long as you know the order of your data, and you use the separator as only a separator, and never as part of your data.
Another way is to precede each write to the pipe with the number of bytes to follow, in a fixed width. Thus, you will know how much data is about to come down the pipe. Use a fixed width, so you know exactly how long the width field will be, so you know both when to start and stop reading each chunk of data.
Problem
Consider the following code: writer.c ``` mkfifo("/tmp/myfifo", 0660); int fd = open("/tmp/myfifo", O_WRONLY); char *foo, *bar; ... write(fd, foo, strlen(foo)*sizeof(char)); write(fd, bar, strlen(bar)*sizeof(char)); ``` reader.c ``` int fd = open("/tmp/myfifo", O_RDONLY); char buf[100]; read(fd, buf, ??); ``` My question is: Since it's not know before hand how many bytes will foo and bar have, how can I know how many bytes to read from reader.c? Because if I, for example, read 10 bytes in reader and foo and bar are together less than 10 bytes, I will have them both in the same variable and that I do not want. Ideally I would have one read function for every variable, but again I don't know before hand how many bytes will the data have. I thought about adding another write instruction in writer.c between the write for foo and bar with a separator and then I would have no problem decoding it from reader.c. Is this the way to go about it? Thanks.