explain_strtoul

const char *explain_strtoul(const char *nptr, char **endptr, int base);

The explain_strtoul function is used to obtain an explanation of an error returned by the strtoul(3) 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.

nptr

The original nptr, exactly as passed to the strtoul(3) system call.

endptr

The original endptr, exactly as passed to the strtoul(3) system call.

base

The original base, exactly as passed to the strtoul(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.

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:

{

    exit(EXIT_FAILURE);
}

The above code example is available pre‐packaged as the explain_strtoul_or_die(3) function.

explain_errno_strtoul

const char *explain_errno_strtoul(int errnum, const char *nptr, char **endptr, int base);

The explain_errno_strtoul function is used to obtain an explanation of an error returned by the strtoul(3) 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.

nptr

The original nptr, exactly as passed to the strtoul(3) system call.

endptr

The original endptr, exactly as passed to the strtoul(3) system call.

base

The original base, exactly as passed to the strtoul(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.

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:

{


    int err = errno;

    exit(EXIT_FAILURE);
}

The above code example is available pre‐packaged as the explain_strtoul_or_die(3) function.

explain_message_strtoul

void explain_message_strtoul(char *message, int message_size, const char *nptr, char **endptr, int base);

The explain_message_strtoul function is used to obtain an explanation of an error returned by the strtoul(3) 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.

nptr

The original nptr, exactly as passed to the strtoul(3) system call.

endptr

The original endptr, exactly as passed to the strtoul(3) system call.

base

The original base, exactly as passed to the strtoul(3) system call.

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

{


    char message[3000];

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


    exit(EXIT_FAILURE);
}

The above code example is available pre‐packaged as the explain_strtoul_or_die(3) function.

explain_message_errno_strtoul

void explain_message_errno_strtoul(char *message, int message_size, int errnum, const char *nptr, char **endptr, int base);

The explain_message_errno_strtoul function is used to obtain an explanation of an error returned by the strtoul(3) 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.

nptr

The original nptr, exactly as passed to the strtoul(3) system call.

endptr

The original endptr, exactly as passed to the strtoul(3) system call.

base

The original base, exactly as passed to the strtoul(3) system call.

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

{


    int err = errno;


    char message[3000];

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


    exit(EXIT_FAILURE);
}

The above code example is available pre‐packaged as the explain_strtoul_or_die(3) function.