gai_cancel - Linux

Overview

gai_cancel() is a Linux system call used to cancel a pending asynchronous name resolution request initiated by the gai_async() function. It allows a process to gracefully terminate an outstanding name resolution operation, freeing up system resources and preventing unnecessary processing.

Syntax

int gai_cancel(gaicb_t *handle);

Options/Flags

None

Examples

Example 1: Cancel an in-progress name resolution request

#include <sys/socket.h>
#include <netdb.h>

int main() {
    struct gaicb handle;

    // Initialize and start a name resolution request
    if (gai_async(&handle, NULL, NULL, NULL, NULL) != 0) {
        perror("gai_async");
        exit(EXIT_FAILURE);
    }

    // Cancel the request
    gai_cancel(&handle);

    return 0;
}

Common Issues

• Resource leaks: If a process makes several gai_async() calls without properly canceling the requests, it can exhaust system resources.
• Erroneous results: An asynchronous name resolution request may return outdated or incorrect results if it is canceled prematurely.

Integration

gai_cancel() can be integrated with other system calls, such as select() or poll(), to monitor the status of asynchronous name resolution requests and cancel them when desired.

Related Commands

• gai_async(): Initiates an asynchronous name resolution request.
• getnameinfo(): Provides name resolution functionality without asynchronous support.