Hi, I have been testing sample code from the wiki and found that libdispatch is alloc'ing a lot of memory without releasing it, both in OS X (Lion 10.7.3, Xcode 4.3.2) and Linux (manually compiled and installed).
The code creates a SIGHUP signal source, with a handler that calls 100_000 writes to a logfile. The write to a log is queued in a serial queue.
The first run shows normal memory usage (8-9 MiB both Linux and OS X). After sending a "kill -1 <pid>" memory usage increases 1-20MiB every time I send the SIGHUP signal.
I have tried compiling with -fobj-arc and without it, but the result is the same. I removed the NSString usage in the br_log function, but the leak is not there: it is somewhere inside libdispatch.
I tried both valgrind and Xcode Instruments, but no leaks are found. Thanks in advance,
//
// main.m
// test02
//
// Created by Aldrin Martoq on 4/29/12.
// Copyright (c) 2012 __MyCompanyName__. All rights reserved.
//
#include <unistd.h>
#import <Foundation/Foundation.h>
#import <dispatch/dispatch.h>
static FILE *log_file = NULL;
static NSString *log_filename = @"/tmp/br.log";
static dispatch_queue_t log_queue;
void br_log(NSString *format, ...) {
@autoreleasepool {
va_list ap;
va_start(ap, format);
NSString *s = [[NSString alloc] initWithFormat:format arguments:ap];
va_end(ap);
if (log_file == NULL) {
log_queue = dispatch_queue_create("cl.martoq.log_queue", NULL);
log_file = fopen([log_filename cStringUsingEncoding:NSUTF8StringEncoding], "a");
NSLog(@"Log file created: %@", log_filename);
}
dispatch_async(log_queue, ^{
@autoreleasepool {
const char *c = [s cStringUsingEncoding:NSUTF8StringEncoding];
fputs(c, log_file);
fputs("\n", log_file);
fflush(log_file);
[s release];
}
});
}
}
void br_setup() {
signal(SIGHUP, SIG_IGN);
dispatch_source_t sig_src = dispatch_source_create(DISPATCH_SOURCE_TYPE_SIGNAL, SIGHUP, 0, dispatch_get_main_queue());
dispatch_source_set_event_handler(sig_src, ^{
dispatch_async(dispatch_get_main_queue(), ^{
printf("Caught SIGHUP\n");
for (int i = 0; i < 100000; i++) {
br_log(@"prueba: %d", i);
}
});
});
dispatch_resume(sig_src);
}
int main(int argc, const char * argv[]) {
@autoreleasepool {
// insert code here...
NSLog(@"Hello, World!");
br_setup();
dispatch_main();
}
return 0;
}