perhaps like this
#include <stdio.h>
int main() {
fprintf(stdout, "This is from hello to stdout\n");
fprintf(stderr, "This is from hello to stderr\n");
return 0;
}
Run
and our nim file
import os, osproc, selectors
when defined(windows):
import streams
proc main =
when defined(linux):
let prc = startProcess("./a.out", options = {})
let errh = errorHandle prc
let outh = outputHandle prc
var stor = newSelector[string]()
defer: stor.close()
stor.registerHandle(int errh, {Read}, "")
stor.registerHandle(int outh, {Read}, "")
var tempout, temperr: File
running = tempout.open(outh)
running = temperr.open(errh)
var running = true
while running:
let keys = stor.select -1
for k in keys:
if k.errorCode.int != 0:
echo k.errorCode.osErrorMsg()
running = false
continue
if k.fd == outh:
echo "stdout: ", tempout.readLine
elif k.fd == errh:
echo "stderr: ", temperr.readLine
close prc
else:
echo "on windows"
let prc = startProcess("./a.exe", options = {})
var errstream = errorStream prc
var outstream = outputStream prc
while true:
var data = errstream.readLine
if data == "":
break
else:
echo "stderr: ", data
data = outstream.readLine
if data == "":
break
else:
echo "stdout: ", data
main()
Run
Note that on windows, selectors doesn't work with file, trying to use
createIoCompletionPort apparently couldn't work because the pipe is busy,
because of this also we cannot use ReOpenFile to enable flag
FILE_FLAG_OVERLAPPED. But, we got stream there so we can emulate async with
peek proc variants (peekStr and peekLine). cmiiw
