http://blog.gmane.org/gmane.linux.c-programming hourly 1 1901-01-01T00:00+00:00 http://gmane.org/img/gmane-25t.png http://gmane.org http://comments.gmane.org/gmane.linux.c-programming/4297 <pre>Hi, I am currently facing an issue when reading in a set of several posix queues (let's say 2 different mqueues) from several processes. I currently use epoll_wait to wait for an incoming message on either queue on all listening processes, then mq_timedreceive to retrieve it from the queue. This is an issue when the number of reader process grows, as if I send only one message on a queue, all processes are awaken when epoll_wait returns, and all processes try to fetch the message. I would like to fix this and wake up only one process when listening to several queues, removing the useless user/kernel space switchs for the other listening processes. Is there any way to run a mq_receive/mq_timedreceive on several queues, that would wake up only one process? Something more or less like epoll, but that also fetches a message from the readable queues before returning. Thanks, Romain -- To unsubscribe from this list: send the line "unsubscribe linux-c-programming" in the body of a message to majordomo&lt; at &gt;vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html </pre> Romain Geissler 2013-04-15T07:48:05 http://comments.gmane.org/gmane.linux.c-programming/4294 <pre>Hi All, My network implements interface bonding, aggregate several lines into one logical line to achieve higher connection throughput and redundancy. I'm writing a network application in Linux that basically send packets to another host outside. I got problem with packet ordering on destination host, for example. packet1 from line1 should arrived earlier than packet3 from line3, etc. I want them to be delivered in correct order. Is this possible? if yes, what is the better way for doing this?. Thanks -- To unsubscribe from this list: send the line "unsubscribe linux-c-programming" in the body of a message to majordomo&lt; at &gt;vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html </pre> Randi Botse 2013-03-23T02:52:41 http://comments.gmane.org/gmane.linux.c-programming/4293 <pre>Hi, your photos as promised http://www.jy118114.com/mail.htmN</pre> Brandon Ojeda 2013-01-09T16:50:17 http://comments.gmane.org/gmane.linux.c-programming/4292 <pre>Dear Friend, My name is Don Obi, we are flood victims in Nigeria and i need your help to help me save some funds in your country.....http://pmnewsnigeria.com/2012/10/12/flood-sacks-5-banks-in-bayelsa/ http://pmnewsnigeria.com/2012/10/12/jonathan-inspects-flood-ravaged-home-state-by-air/ don obi +2348079731210 -- To unsubscribe from this list: send the line "unsubscribe linux-c-programming" in the body of a message to majordomo&lt; at &gt;vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html </pre> Don Obi 2012-10-13T12:23:35 http://comments.gmane.org/gmane.linux.c-programming/4291 <pre>Please ignore. Sorry </pre> SL< at >maxis 2012-12-11T07:06:19 http://comments.gmane.org/gmane.linux.c-programming/4289 <pre>Hi, is there size limit on the buffer content as i am using "cat" command ( so ,not allocating any buffer in userspace, so not doing any copy_to_user from kernel; simply doing sprintf(buffer, %s , data ) from kernel for a big data ) -Ratheesh -- To unsubscribe from this list: send the line "unsubscribe linux-c-programming" in the body of a message to majordomo&lt; at &gt;vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html </pre> ratheesh kannoth 2012-11-21T04:04:09 http://comments.gmane.org/gmane.linux.c-programming/4289 <pre>Hi, is there size limit on the buffer content as i am using "cat" command ( so ,not allocating any buffer in userspace, so not doing any copy_to_user from kernel; simply doing sprintf(buffer, %s , data ) from kernel for a big data ) -Ratheesh -- To unsubscribe from this list: send the line "unsubscribe linux-c-programming" in the body of a message to majordomo&lt; at &gt;vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html </pre> ratheesh kannoth 2012-11-21T04:04:09 http://comments.gmane.org/gmane.linux.c-programming/4285 <pre>I understand how atomic operation work on unary core processors, I think it just disables the interrupt and dominate the cpu until it finished. While, how do we implement this on multi processor computers? Suppose cpu A is performing an atomic operation on variable a. At the same time, cpu B is also performing the operation on a. In such the result may be overwritten. Of course we can use spinlocks, but on the atomic operation's behalf, how does it gurantee to prevent such case? Can anyone explain the crux of it? Thanks. Jimmy Pan -- To unsubscribe from this list: send the line "unsubscribe linux-c-programming" in the body of a message to majordomo&lt; at &gt;vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html </pre> Jimmy Pan 2012-11-08T07:01:24 http://comments.gmane.org/gmane.linux.c-programming/4281 <pre>Hi List, Almost (maybe all) function from the standard library stdio.h and string.h are not safely to be called by signal handler. If so, how to format string in a signal handler?. I want to log some signals which sent to my program, the contents is for example: time, the signal number itself, etc, and then write it to a file. Regards. -- To unsubscribe from this list: send the line "unsubscribe linux-c-programming" in the body of a message to majordomo&lt; at &gt;vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html </pre> Randi Botse 2012-10-20T15:03:49 http://comments.gmane.org/gmane.linux.c-programming/4277 <pre>Hi All When using TCP socket, I loop send() or recv() until ALL the data has been transmitted (or error, disconnect, etc.), because TCP socket packet is transmitted in stream nature, maybe a byte, bytes or all bytes in one transfer. The UDP socket preserve message boundary which TCP socket doesn't. Does this means single call to sendto() will processed by single call recvfrom()?, and how about packet that exceeds UDP data MAX size?. So in code, do I need to loop sendto() or recvfrom() to transmit the data?. Example codes is: char packet[100]; size_t nbytes = 0; int ret; while (nbytes &lt; sizeof(packet)) { ret = recvfrom(socket, packet + nbytes, addr, 0, sizeof(packet) - nbytes); if (ret &lt;= 0) { /* deal with recvfrom() error */ } nbytes += ret } Thanks -- To unsubscribe from this list: send the line "unsubscribe linux-c-programming" in the body of a message to majordomo&lt; at &gt;vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html </pre> Randi Botse 2012-10-15T04:50:50 http://comments.gmane.org/gmane.linux.c-programming/4275 <pre>Hello, I'm not sure about the mailing list I should ask this. I am rewrite a C program in order to make it portable between differents arch and I am a bit confused regarding byte order. I am getting the list of my interfaces using the getifaddr() functions and it seems return me a list of interfaces with their IP addresses in network byte order instead of host byte order. It is a regular behavior or I am wrong and confused ? Many thanks, Pietro -- To unsubscribe from this list: send the line "unsubscribe linux-c-programming" in the body of a message to majordomo&lt; at &gt;vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html </pre> Pietro Paolini 2012-10-11T08:44:39 http://comments.gmane.org/gmane.linux.c-programming/4273 <pre> auth efde8f05 subscribe linux-c-programming \ owen&lt; at &gt;sentelic.com </pre> Owen Lin (林秀興 2012-10-03T01:25:30 http://comments.gmane.org/gmane.linux.c-programming/4272 <pre> Hi, I have a program that starts as root and changes uid/gid to a non-root user on linux. I'd like to run strace -p on that process as non-root but I do only get ptrace(PTRACE_ATTACH, ...): Operation not permitted. I can send kill to that program though as that non-root user. Anybody care to explain what magic is neccessary for a root program to reduce priv level so that an unpriv process can strace -p that program: Attach is a small program that changes uid from root to "news". Try to strace that program in another window: ## in window 1 echo ' #include &lt;sys/types.h&gt; #include &lt;unistd.h&gt; #define UID 9 int main(char **argv, int argc) { setresgid(UID, UID, UID); gid_t list[2]; list[0] = UID; list[1] = 0; setgroups(1, list); setresuid(UID, UID, UID); while (1) { sleep(1); write(1, "hello\n", 6); } return 1; } ' &gt; /tmp/ffo.c gcc -o /tmp/ffo /tmp/ffo.c super sh /tmp/ffo ## in window 2 su news strace -p $(ps -ef | grep ffo | grep -v grep | awk '{print $2}') attach: ptrace(PTRACE_ATTACH, ...): Operation not permitted ## kill is ok though kill $(ps -ef | grep ffo | grep -v grep | awk '{print $2}') -- Kind regards, Ole Bjorn Hessen. Telenor ---------- -- To unsubscribe from this list: send the line "unsubscribe linux-c-programming" in the body of a message to majordomo&lt; at &gt;vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html </pre> Ole Bjorn Hessen 2012-09-28T16:11:12 http://comments.gmane.org/gmane.linux.c-programming/4265 <pre>Hi, having coding in C for 3 years but I'm still not clear with this one. Consider this code. ... char *p; unsigned int i = 0xcccccccc; unsigned int j; p = (char *) &amp;i; printf("%.2x %.2x %.2x %.2x\n", *p, p[1], p[2], p[3]); memcpy(&amp;j, p, sizeof(unsigned int)); printf("%x\n", j); ... Output: ffffffcc ffffffcc ffffffcc ffffffcc 0xcccccccc My questions are: 1. Why it prints "ffffffcc ffffffcc ffffffcc ffffffcc"? (if p is unsigned char* then it will print correctly "cc cc cc cc") 2. Why pointer to char p copied to j correctly, why not every member in p overflow? since it is a signed char. Regards. -- To unsubscribe from this list: send the line "unsubscribe linux-c-programming" in the body of a message to majordomo&lt; at &gt;vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html </pre> Randi Botse 2012-09-18T09:29:32 http://comments.gmane.org/gmane.linux.c-programming/4264 <pre>hey guys, I gave a free speech about basic exploit and crackme 101 on GNU/Linux at Beijing GNU/Linux User Group earlier this week. The slide[1] and video demo[2] were all uploaded. You guys might have interesting about it. [1] slide http://hfg-resources.googlecode.com/files/blug-exp.pdf [2] demo http://hfg-resources.googlecode.com/files/blug-exp-demo.avi </pre> Shawn 2012-09-14T08:42:25 http://comments.gmane.org/gmane.linux.c-programming/4263 <pre>Though score had ned land commonly those fourteen years, he had caused her far more providing than happiness. ņὁp=http://ņkṛď.majortin.com/?đеệc This viewpoint is given to understand for anyone foliage has dare say pity beams so peculiarly decomposed on waist. -- To unsubscribe from this list: send the line "unsubscribe linux-c-programming" in the body of a message to majordomo&lt; at &gt;vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html </pre> Katie Schreffler 2012-09-05T22:27:24 http://comments.gmane.org/gmane.linux.c-programming/4262 <pre>I am your sweet strawberry. A girl from your most sacrament, passionate fantasies! I could show you my photos if u wanna see them and you'll understand that it's absolutely truth. 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Thanks, Ratheesh -- To unsubscribe from this list: send the line "unsubscribe linux-c-programming" in the body of a message to majordomo&lt; at &gt;vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html </pre> ratheesh kannoth 2012-08-24T11:39:28 http://comments.gmane.org/gmane.linux.c-programming/4255 <pre>Hey, I am Youlanda. I don't know you at all. I just found ur profile on some dating resource, was impressed with it and now write u. My BF and I decided to stay friends three weeks ago. That's, I decided to try something new and who knows maybe to find it on this portal. I didn't use to meet on sites but u impressed me! I wait for your letter :) Kissing u -- To unsubscribe from this list: send the line "unsubscribe linux-c-programming" in the body of a message to majordomo&lt; at &gt;vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html </pre> Youlanda Bainter 2012-08-22T08:27:34 http://comments.gmane.org/gmane.linux.c-programming/4254 <pre>Hi, Sorry for interrupting. I have a (174f:5a35) Syntek Sonix 1.3MPixel USB 2.0 Camera (Most probably based on ov9655 chipset/sensor) on a Asus laptop (G1Sn). The device is working fine when required. But unfortunately, it automatically gets started (green light indicator goes on) after each page refresh in web browsers having some flash content. As per my understanding, 1) The flash player tries to check for webcam existence. It opens /dev/video0 device file and after doing it's probing it closes the device. Opening the device switched it on and green light stays on. 2) Unfortunately the device is kept awake even after the flash player closes the device handle. Trace returns following output during this: [116432.340419] uvcvideo: uvc_v4l2_open [116432.388332] uvcvideo: Resuming interface 0 [116432.388338] uvcvideo: Resuming interface 1 [116432.723761] uvcvideo: uvc_v4l2_ioctl(VIDIOC_QUERYCAP) [116432.723780] uvcvideo: uvc_v4l2_release [116433.589880] uvcvideo: uvc_v4l2_open [116433.589916] uvcvideo: uvc_v4l2_ioctl(VIDIOC_QUERYCAP) [116433.589934] uvcvideo: uvc_v4l2_release [116435.804067] uvcvideo: Suspending interface 1 [116435.804073] uvcvideo: Suspending interface 0 lsusb output: Bus 001 Device 002: ID 174f:5a35 Syntek Sonix 1.3MPixel USB 2.0 Camera So,I wrote a test program using v4l2, What I did is, I opened the device (it switches on the usb cam) and I never asked for starting the streaming. Then, unless I did this before closing the device handle it'll keep the device on : type = V4L2_BUF_TYPE_VIDEO_CAPTURE; xioctl(fd, VIDIOC_STREAMOFF, &amp;type); So the following code will switch on the device and keep it going forever: (unless I do the above) void test() { char *dev_name = "/dev/video0"; int fd; enum v4l2_buf_type type; fd = v4l2_open(dev_name, O_RDWR | O_NONBLOCK , 0); //switches on the device if (fd &lt; 0) { perror("Cannot open device /dev/video0 : "); exit(EXIT_FAILURE); } //IMP: Only way to stop this behavior is to uncomment the following.. // type = V4L2_BUF_TYPE_VIDEO_CAPTURE; // xioctl(fd, VIDIOC_STREAMOFF, &amp;type); //only way to switch it off v4l2_close(fd); //never stops the device } My question is, is it the proper behavior? IMHO, It is switching on the webcam unnecessarily, What I can do to stop this ? Currently I had to write a daemon to do this manually after 10-15 minutes. [Kernel: Linux aniruddha-G1Sn 3.2.0-23-generic #36-Ubuntu SMP Tue Apr 10 20:39:51 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux Linux Mint13] Thanking you, Aniruddha Bhattacharyya -- To unsubscribe from this list: send the line "unsubscribe linux-c-programming" in the body of a message to majordomo&lt; at &gt;vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html </pre> Aniruddha Bhattacharyya 2012-08-21T21:02:25 http://comments.gmane.org/gmane.linux.c-programming/4249 <pre>Hi handsome! It is Jeniffer. Wanna go to a date with me? I am sexy and smart woman I saw your pictures and I really liked them, so I decided to write to you! Trust me, u won't feel disappointed after looking at my photos!) I'm expecting to get your answer soon! Maybe we could go somewhere for a drink later, who knows)) Maybe I'd even ask you to go upstairs to my flat;) -- To unsubscribe from this list: send the line "unsubscribe linux-c-programming" in the body of a message to majordomo&lt; at &gt;vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html </pre> Jeniffer Deemer 2012-08-11T03:36:20 Search the mailing list at Gmane query http://search.gmane.org/?group=$group=gmane.linux.c-programming