explain_strtod(3)

NAME
explain_strtod - explain strtod(3) errors

SYNOPSIS
#include <libexplain/strtod.h>

const char *explain_strtod(const char *nptr, char **endptr);
const char *explain_errno_strtod(int errnum, const char *nptr, char **endptr);
void explain_message_strtod(char *message, int message_size, const char *nptr, char **endptr);
void explain_message_errno_strtod(char *message, int message_size, int errnum, const char *nptr, char **endptr);

DESCRIPTION
These functions may be used to obtain explanations for errors returned by the strtod(3) system call.

  explain_strtod
const char *explain_strtod(const char *nptr, char **endptr);

The explain_strtod function is used to obtain an explanation of an error returned by the strtod(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 strtod(3) system call.

endptr
    The original endptr, exactly as passed to the strtod(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:
    double result = strtod(nptr, endptr);
    if (result < 0)
    {
    fprintf(stderr, "%s\n", explain_strtod(nptr, endptr));
        exit(EXIT_FAILURE);
    }

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

  explain_errno_strtod
const char *explain_errno_strtod(int errnum, const char *nptr, char **endptr);

The explain_errno_strtod function is used to obtain an explanation of an error returned by the strtod(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 strtod(3) system call.

endptr
    The original endptr, exactly as passed to the strtod(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:
    double result = strtod(nptr, endptr);
    if (result < 0)
    {
        int err = errno;
    fprintf(stderr, "%s\n", explain_errno_strtod(err, nptr, endptr));
        exit(EXIT_FAILURE);
    }

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

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

The explain_message_strtod function is used to obtain an explanation of an error returned by the strtod(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 strtod(3) system call.

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

Example: This function is intended to be used in a fashion similar to the following example:
    double result = strtod(nptr, endptr);
    if (result < 0)
    {
        char message[3000];
    explain_message_strtod(message, sizeof(message), nptr, endptr);
        fprintf(stderr, "%s\n", message);
        exit(EXIT_FAILURE);
    }

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

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

The explain_message_errno_strtod function is used to obtain an explanation of an error returned by the strtod(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 strtod(3) system call.

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

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

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

SEE ALSO

strtod(3)
    convert ASCII string to floating-point number

explain_strtod_or_die(3)
    convert ASCII string to floating-point number and report errors

COPYRIGHT
libexplain version
Copyright (C) 2009 Peter Miller