GSP
Quick Navigator

Search Site

Unix VPS
A - Starter
B - Basic
C - Preferred
D - Commercial
MPS - Dedicated
Previous VPSs
* Sign Up! *

Support
Contact Us
Online Help
Handbooks
Domain Status
Man Pages

FAQ
Virtual Servers
Pricing
Billing
Technical

Network
Facilities
Connectivity
Topology Map

Miscellaneous
Server Agreement
Year 2038
Credits
 

USA Flag

 

 

Man Pages


Manual Reference Pages  -  EXPLAIN_VASPRINTF (3)

NAME

explain_vasprintf - explain I]vasprintf(3) errors

CONTENTS

Synopsis
Description
See Also
Copyright

SYNOPSIS

#include <libexplain/vasprintf.h>

const char *explain_vasprintf(char **data, const char *format, va_list ap);
const char *explain_errno_vasprintf(int errnum, char **data, const char *format, va_list ap);
void explain_message_vasprintf(char *message, int message_size, char **data, const char *format, va_list ap);
void explain_message_errno_vasprintf(char *message, int message_size, int errnum, char **data, const char *format, va_list ap);

DESCRIPTION

These functions may be used to obtain explanations for errors returned by the I]vasprintf(3) system call.

    explain_vasprintf

const char *explain_vasprintf(char **data, const char *format, va_list ap);

The B]explain_vasprintf function is used to obtain an explanation of an error returned by the I]vasprintf(3) system call. The least the message will contain is the value of CW]strerror(errno), but usually it will do much better, and indicate the underlying cause in more detail.

The I]errno global variable will be used to obtain the error value to be decoded.
I]data The original data, exactly as passed to the I]vasprintf(3) system call.
I]format The original format, exactly as passed to the I]vasprintf(3) system call.
I]ap The original ap, exactly as passed to the I]vasprintf(3) 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.
B]Note: This function is B]not thread safe, because it shares a return buffer across all threads, and many other functions in this library.

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

errno = 0; int result = vasprintf(data, format, ap);
if (result < 0 || errno != 0)
{

fprintf(stderr, "%s\n", explain_vasprintf(data, format, ap));
    exit(EXIT_FAILURE);
}

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

    explain_errno_vasprintf

const char *explain_errno_vasprintf(int errnum, char **data, const char *format, va_list ap);

The B]explain_errno_vasprintf function is used to obtain an explanation of an error returned by the I]vasprintf(3) system call. The least the message will contain is the value of CW]strerror(errno), but usually it will do much better, and indicate the underlying cause in more detail.
I]errnum The error value to be decoded, usually obtained from the I]errno global variable just before this function is called. This is necessary if you need to call B]any code between the system call to be explained and this function, because many libc functions will alter the value of I]errno.
I]data The original data, exactly as passed to the I]vasprintf(3) system call.
I]format The original format, exactly as passed to the I]vasprintf(3) system call.
I]ap The original ap, exactly as passed to the I]vasprintf(3) 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.
B]Note: This function is B]not thread safe, because it shares a return buffer across all threads, and many other functions in this library.

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

errno = 0; int result = vasprintf(data, format, ap);
if (result < 0 || errno != 0)
{
    int err = errno;

fprintf(stderr, "%s\n", explain_errno_vasprintf(err, data, format, ap));
    exit(EXIT_FAILURE);
}

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

    explain_message_vasprintf

void explain_message_vasprintf(char *message, int message_size, char **data, const char *format, va_list ap);

The B]explain_message_vasprintf function is used to obtain an explanation of an error returned by the I]vasprintf(3) system call. The least the message will contain is the value of CW]strerror(errno), but usually it will do much better, and indicate the underlying cause in more detail.

The I]errno global variable will be used to obtain the error value to be decoded.
I]message
  The location in which to store the returned message. If a suitable message return buffer is supplied, this function is thread safe.
I]message_size
  The size in bytes of the location in which to store the returned message.
I]data The original data, exactly as passed to the I]vasprintf(3) system call.
I]format The original format, exactly as passed to the I]vasprintf(3) system call.
I]ap The original ap, exactly as passed to the I]vasprintf(3) system call.
B]Example: This function is intended to be used in a fashion similar to the following example:

errno = 0; int result = vasprintf(data, format, ap);
if (result < 0 || errno != 0)
{
    char message[3000];



explain_message_vasprintf(message, sizeof(message), data, format, ap);


    fprintf(stderr, "%s\n", message);
    exit(EXIT_FAILURE);
}

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

    explain_message_errno_vasprintf

void explain_message_errno_vasprintf(char *message, int message_size, int errnum, char **data, const char *format, va_list ap);

The B]explain_message_errno_vasprintf function is used to obtain an explanation of an error returned by the I]vasprintf(3) system call. The least the message will contain is the value of CW]strerror(errno), but usually it will do much better, and indicate the underlying cause in more detail.
I]message
  The location in which to store the returned message. If a suitable message return buffer is supplied, this function is thread safe.
I]message_size
  The size in bytes of the location in which to store the returned message.
I]errnum The error value to be decoded, usually obtained from the I]errno global variable just before this function is called. This is necessary if you need to call B]any code between the system call to be explained and this function, because many libc functions will alter the value of I]errno.
I]data The original data, exactly as passed to the I]vasprintf(3) system call.
I]format The original format, exactly as passed to the I]vasprintf(3) system call.
I]ap The original ap, exactly as passed to the I]vasprintf(3) system call.
B]Example: This function is intended to be used in a fashion similar to the following example:

errno = 0; int result = vasprintf(data, format, ap);
if (result < 0 || errno != 0)
{
    int err = errno;
    char message[3000];



explain_message_errno_vasprintf(message, sizeof(message), err, data, format, ap);


    fprintf(stderr, "%s\n", message);
    exit(EXIT_FAILURE);
}

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

SEE ALSO

I]vasprintf(3)
  print to allocated string
I]explain_vasprintf_or_die(3)
  print to allocated string and report errors

COPYRIGHT

libexplain version 1.3
Copyright © 2013 Peter Miller
Search for    or go to Top of page |  Section 3 |  Main Index


EXPLAIN_VASPRINTF (3) -->

Powered by GSP Visit the GSP FreeBSD Man Page Interface.
Output converted with manServer 1.07.