explain_kill(3)

NAME
explain_kill - explain kill(2) errors

SYNOPSIS
#include <libexplain/kill.h>

const char *explain_kill(pid_t pid, int sig);
const char *explain_errno_kill(int errnum, pid_t pid, int sig);
void explain_message_kill(char *message, int message_size, pid_t pid, int sig);
void explain_message_errno_kill(char *message, int message_size, int errnum, pid_t pid, int sig);

DESCRIPTION
These functions may be used to obtain explanations for errors returned by the kill(2) system call.

  explain_kill
const char *explain_kill(pid_t pid, int sig);

The explain_kill function is used to obtain an explanation of an error returned by the kill(2) system call. The least the message will contain is the value of strerror(errno), but usually it will do much better, and indicate the underlying cause in more detail.

The errno global variable will be used to obtain the error value to be decoded.

pid The original pid, exactly as passed to the kill(2) system call.

sig The original sig, exactly as passed to the kill(2) system call.

Returns:
    The message explaining the error. This message buffer is shared by all libexplain functions which do not supply a buffer in their argument list. This will be overwritten by the next call to any libexplain function which shares this buffer, including other threads.

Note: This function is not thread safe, because it shares a return buffer across all threads, and many other functions in this library.

Example: This function is intended to be used in a fashion similar to the following example:
    if (kill(pid, sig) < 0)
    {
    fprintf(stderr, "%s\n", explain_kill(pid, sig));
        exit(EXIT_FAILURE);
    }

The above code example is available pre-packaged as the explain_kill_or_die(3) function.

  explain_errno_kill
const char *explain_errno_kill(int errnum, pid_t pid, int sig);

The explain_errno_kill function is used to obtain an explanation of an error returned by the kill(2) system call. The least the message will contain is the value of strerror(errno), but usually it will do much better, and indicate the underlying cause in more detail.

errnum
    The error value to be decoded, usually obtained from the errno global variable just before this function is called. This is necessary if you need to call any code between the system call to be explained and this function, because many libc functions will alter the value of errno.

pid The original pid, exactly as passed to the kill(2) system call.

sig The original sig, exactly as passed to the kill(2) system call.

Returns:
    The message explaining the error. This message buffer is shared by all libexplain functions which do not supply a buffer in their argument list. This will be overwritten by the next call to any libexplain function which shares this buffer, including other threads.

Note: This function is not thread safe, because it shares a return buffer across all threads, and many other functions in this library.

Example: This function is intended to be used in a fashion similar to the following example:
    if (kill(pid, sig) < 0)
    {
        int err = errno;
    fprintf(stderr, "%s\n", explain_errno_kill(err, pid, sig));
        exit(EXIT_FAILURE);
    }

The above code example is available pre-packaged as the explain_kill_or_die(3) function.

  explain_message_kill
void explain_message_kill(char *message, int message_size, pid_t pid, int sig);

The explain_message_kill function is used to obtain an explanation of an error returned by the kill(2) system call. The least the message will contain is the value of strerror(errno), but usually it will do much better, and indicate the underlying cause in more detail.

The errno global variable will be used to obtain the error value to be decoded.

message
    The location in which to store the returned message. If a suitable message return buffer is supplied, this function is thread safe.

message_size
    The size in bytes of the location in which to store the returned message.

pid The original pid, exactly as passed to the kill(2) system call.

sig The original sig, exactly as passed to the kill(2) system call.

Example: This function is intended to be used in a fashion similar to the following example:
    if (kill(pid, sig) < 0)
    {
        char message[3000];
    explain_message_kill(message, sizeof(message), pid, sig);
        fprintf(stderr, "%s\n", message);
        exit(EXIT_FAILURE);
    }

The above code example is available pre-packaged as the explain_kill_or_die(3) function.

  explain_message_errno_kill
void explain_message_errno_kill(char *message, int message_size, int errnum, pid_t pid, int sig);

The explain_message_errno_kill function is used to obtain an explanation of an error returned by the kill(2) system call. The least the message will contain is the value of strerror(errno), but usually it will do much better, and indicate the underlying cause in more detail.

message
    The location in which to store the returned message. If a suitable message return buffer is supplied, this function is thread safe.

message_size
    The size in bytes of the location in which to store the returned message.

errnum
    The error value to be decoded, usually obtained from the errno global variable just before this function is called. This is necessary if you need to call any code between the system call to be explained and this function, because many libc functions will alter the value of errno.

pid The original pid, exactly as passed to the kill(2) system call.

sig The original sig, exactly as passed to the kill(2) system call.

Example: This function is intended to be used in a fashion similar to the following example:
    if (kill(pid, sig) < 0)
    {
        int err = errno;
        char message[3000];
    explain_message_errno_kill(message, sizeof(message), err, pid, sig);
        fprintf(stderr, "%s\n", message);
        exit(EXIT_FAILURE);
    }

The above code example is available pre-packaged as the explain_kill_or_die(3) function.

SEE ALSO

kill(2)
    send signal to a process

explain_kill_or_die(3)
    send signal to a process and report errors

COPYRIGHT
libexplain version 1.1
Copyright (C) 2009 Peter Miller