explain_strtod_or_die(3) [debian man page]
explain_strtod_or_die(3) Library Functions Manual explain_strtod_or_die(3) NAME
explain_strtod_or_die - convert string to number and report errors SYNOPSIS
#include <libexplain/strtod.h> double explain_strtod_or_die(const char *nptr, char **endptr); double explain_strtod_on_error(const char *nptr, char **endptr)) DESCRIPTION
The explain_strtod_or_die function is used to call the strtod(3) system call. On failure an explanation will be printed to stderr, obtained from the explain_strtod(3) function, and then the process terminates by calling exit(EXIT_FAILURE). The explain_strtod_on_error function is used to call the strtod(3) system call. On failure an explanation will be printed to stderr, obtained from the explain_strtod(3) function, but still returns to the caller. nptr The nptr, exactly as to be passed to the strtod(3) system call. endptr The endptr, exactly as to be passed to the strtod(3) system call. RETURN VALUE
The explain_strtod_or_die function only returns on success, see strtod(3) for more information. On failure, prints an explanation and exits, it does not return. The explain_strtod_on_error function always returns the value return by the wrapped strtod(3) system call. EXAMPLE
The explain_strtod_or_die function is intended to be used in a fashion similar to the following example: double result = explain_strtod_or_die(nptr, endptr); SEE ALSO
strtod(3) convert ASCII string to floating-point number explain_strtod(3) explain strtod(3) errors exit(2) terminate the calling process COPYRIGHT
libexplain version 0.52 Copyright (C) 2009 Peter Miller explain_strtod_or_die(3)
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explain_strtod(3) Library Functions Manual 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 ", 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 neces- sary 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 ", 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 mes- sage 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 ", 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 neces- sary 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 ", 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 0.52 Copyright (C) 2009 Peter Miller explain_strtod(3)