man explain_wait3 (3): explain wait3(2) errors

SYNOPSIS

#include <libexplain/wait3.h>

const char *explain_wait3(int *status, int options, struct rusage *rusage);
const char *explain_errno_wait3(int errnum, int *status, int options, struct rusage *rusage);
void explain_message_wait3(char *message, int message_size, int *status, int options, struct rusage *rusage);
void explain_message_errno_wait3(char *message, int message_size, int errnum, int *status, int options, struct rusage *rusage);

DESCRIPTION

These functions may be used to obtain explanations for errors returned by the wait3(2) system call.

explain_wait3

const char *explain_wait3(int *status, int options, struct rusage *rusage);

The explain_wait3 function is used to obtain an explanation of an error returned by the wait3(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.

This function is intended to be used in a fashion similar to the following example:

int pid = wait3(status, options, rusage);
if (pid < 0)
{
    fprintf(stderr, "%s\n", explain_wait3(status, options, rusage));
    exit(EXIT_FAILURE);
}

status: The original status, exactly as passed to the wait3(2) system call.
options: The original options, exactly as passed to the wait3(2) system call.
rusage: The original rusage, exactly as passed to the wait3(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.

explain_errno_wait3

const char *explain_errno_wait3(int errnum, int *status, int options, struct rusage *rusage);

The explain_errno_wait3 function is used to obtain an explanation of an error returned by the wait3(2) system call. The least the message will contain is the value of strerror(errnum), but usually it will do much better, and indicate the underlying cause in more detail.

This function is intended to be used in a fashion similar to the following example:

int pid = wait3(status, options, rusage);
if (pid < 0)
{
    int err = errno;
    fprintf(stderr, "%s\n", explain_errno_wait3(err, status, options,
        rusage));
    exit(EXIT_FAILURE);
}

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.
status: The original status, exactly as passed to the wait3(2) system call.
options: The original options, exactly as passed to the wait3(2) system call.
rusage: The original rusage, exactly as passed to the wait3(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.

explain_message_wait3

void explain_message_wait3(char *message, int message_size, int *status, int options, struct rusage *rusage);

The explain_message_wait3 function may be used to obtain an explanation of an error returned by the wait3(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.

This function is intended to be used in a fashion similar to the following example:

int pid = wait3(status, options, rusage);
if (pid < 0)
{
    char message[3000];
    explain_message_wait3(message, sizeof(message),
        status, options, rusage);
    fprintf(stderr, "%s\n", message);
    exit(EXIT_FAILURE);
}

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.
status: The original status, exactly as passed to the wait3(2) system call.
options: The original options, exactly as passed to the wait3(2) system call.
rusage: The original rusage, exactly as passed to the wait3(2) system call.

explain_message_errno_wait3

void explain_message_errno_wait3(char *message, int message_size, int errnum, int *status, int options, struct rusage *rusage);

The explain_message_errno_wait3 function may be used to obtain an explanation of an error returned by the wait3(2) system call. The least the message will contain is the value of strerror(errnum), but usually it will do much better, and indicate the underlying cause in more detail.

This function is intended to be used in a fashion similar to the following example:

int pid = wait3(status, options, rusage);
if (pid < 0)
{
    int err = errno;
    char message[3000];
    explain_message_errno_wait3(message, sizeof(message), err,
        status, options, rusage);
    fprintf(stderr, "%s\n", message);
    exit(EXIT_FAILURE);
}

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.
status: The original status, exactly as passed to the wait3(2) system call.
options: The original options, exactly as passed to the wait3(2) system call.
rusage: The original rusage, exactly as passed to the wait3(2) system call.

SYNOPSIS

DESCRIPTION

explain_wait3

explain_errno_wait3

explain_message_wait3

explain_message_errno_wait3

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