StackOverflow2013

Note that there are some explanatory texts on larger screens.

plurals

PONamed pipes - Problem with write() and read()
text
Body
copied!<p>I am doing programming in C++, under LINUX. I have two independent processes. I should provide communication using named pipe. </p> <p>Reader: -creates FIFO using mkfifo - status = mkfifo(myFIFO, 0666) -opens the pipe using open - fifo = open (myFIFO,O_RDONLY) -reads from the pipe - num = read(fifo, temp, sizeof(temp))</p> <p>Writer: -opens pipe - fifo = open(myFIFO, O_WRONLY); -writes to the pipe - num = write(fifo, string, strlen(string));</p> <p>I have noticed that the file descriptor returned for read process and write process are 0. Also, after command write, I can see on my terminal, the string which should be written to the pipe. I don't know why it is shown on terminal... Also, the number of bytes that are written is 0... </p> <p>Would you please help me? Thank you!!!</p> <pre><code>// read.cpp: #define myFIFO "/temp/FIFO" int main(){ int num, fifo, status; char temp[32]; if (status = mkfifo(myFIFO, 0666) < 0) { printf("\n %s \n", strerror(errno)); return 0; } if (fifo = open(myFIFO, O_RDONLY) < 0) { printf("\n %s \n", strerror(errno)); return 0; } if (num= read(fifo, temp, sizeof(temp)) < 0) { printf("\n %s \n", strerror(errno)); return 0; } printf("In FIFO is %s \n", temp); } </code></pre> <p>And in another file:</p> <pre><code>// write.cpp: #define myFIFO "/temp/FIFO" int main() { int status, num, fifo; char string[]="Testing..."; if (fifo = open(myFIFO, O_WRONLY) < 0) { printf("\n %s \n", strerror(errno)); return 0; } if (num= write(fifo, string, strlen(string)) < 0) { printf("\n %s \n", strerror(errno)); return 0; } } </code></pre>

Querying!

Guidance

An individual column

Larger individual text columns get their own page to allow for proper reading.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload