explain_fgetc(3) Library Functions Manual explain_fgetc(3) NAME explain_fgetc - explain fgetc(3) errors SYNOPSIS #include <libexplain/fgetc.h> const char *explain_fgetc(FILE *fp); const char *explain_errno_fgetc(int errnum, FILE *fp); void explain_message_fgetc(char *message, int message_size, FILE *fp); void explain_message_errno_fgetc(char *message, int message_size, int er- rnum, FILE *fp); DESCRIPTION These functions may be used to obtain explanations for errors returned by the fgetc(3) system call. explain_fgetc const char *explain_fgetc(FILE *fp); The explain_fgetc function is used to obtain an explanation of an error re- turned by the fgetc(3) system call. The least the message will contain is the value of strerror(errno), but usually it will do much better, and indi- cate the underlying cause in more detail. The errno global variable will be used to obtain the error value to be de- coded. This function is intended to be used in a fashion similar to the following example: int c = fgetc(fp); if (c == EOF && ferror(fp)) { fprintf(stderr, "%s\n", explain_fgetc(fp)); exit(EXIT_FAILURE); } fp The original fp, exactly as passed to the fgetc(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 ar- gument list. This will be overwritten by the next call to any lib- explain 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_fgetc const char *explain_errno_fgetc(int errnum, FILE *fp); The explain_errno_fgetc function is used to obtain an explanation of an er- ror returned by the fgetc(3) system call. The least the message will con- tain 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 c = fgetc(fp); if (c == EOF && ferror(fp)) { int err = errno; fprintf(stderr, "%s\n", explain_errno_fgetc(err, fp)); 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 nec- essary 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. fp The original fp, exactly as passed to the fgetc(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 ar- gument list. This will be overwritten by the next call to any lib- explain 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_fgetc void explain_message_fgetc(char *message, int message_size, FILE *fp); The explain_message_fgetc function may be used to obtain an explanation of an error returned by the fgetc(3) system call. The least the message will contain is the value of strerror(errno), but usually it will do much bet- ter, and indicate the underlying cause in more detail. The errno global variable will be used to obtain the error value to be de- coded. This function is intended to be used in a fashion similar to the following example: int c = fgetc(fp); if (c == EOF && ferror(fp)) { char message[3000]; explain_message_fgetc(message, sizeof(message), fp); 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. fp The original fp, exactly as passed to the fgetc(3) system call. explain_message_errno_fgetc void explain_message_errno_fgetc(char *message, int message_size, int er- rnum, FILE *fp); The explain_message_errno_fgetc function may be used to obtain an explana- tion of an error returned by the fgetc(3) system call. The least the mes- sage 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 c = fgetc(fp); if (c == EOF && ferror(fp)) { int err = errno; char message[3000]; explain_message_errno_fgetc(message, sizeof(message), err, fp); 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 nec- essary 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. fp The original fp, exactly as passed to the fgetc(3) system call. SEE ALSO fgetc(3) input of characters explain_fgetc_or_die(3) input of characters and report errors COPYRIGHT libexplain version 1.3 Copyright (C) 2008 Peter Miller explain_fgetc(3)
NAME | SYNOPSIS | DESCRIPTION | SEE ALSO | COPYRIGHT
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