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explain_realloc(3) Library Functions Manual explain_realloc(3) NAME explain_realloc - explain realloc(3) errors SYNOPSIS #include <libexplain/realloc.h> const char *explain_realloc(void *ptr, size_t size); const char *explain_errno_realloc(int errnum, void *ptr, size_t size); void explain_message_realloc(char *message, int message_size, void *ptr, size_t size); void explain_message_errno_realloc(char *message, int message_size, int errnum, void *ptr, size_t size); DESCRIPTION These functions may be used to obtain explanations for errors returned by the realloc(3) system call. explain_realloc const char *explain_realloc(void *ptr, size_t size); The explain_realloc function is used to obtain an explanation of an er- ror returned by the realloc(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. This function is intended to be used in a fashion similar to the fol- lowing example: void *new_ptr = realloc(ptr, size); if (!new_ptr) { fprintf(stderr, "%s\n", explain_realloc(ptr, size)); exit(EXIT_FAILURE); } The above code example is available pre-packaged as the explain_real- loc_or_die(3) function. ptr The original ptr, exactly as passed to the realloc(3) system call. size The original size, exactly as passed to the realloc(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, in- cluding 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_realloc const char *explain_errno_realloc(int errnum, void *ptr, size_t size); The explain_errno_realloc function is used to obtain an explanation of an error returned by the realloc(3) system call. The least the message 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 fol- lowing example: void *new_ptr = realloc(ptr, size); if (!new_ptr) { int err = errno; fprintf(stderr, "%s\n", explain_errno_realloc(err, ptr, size)); exit(EXIT_FAILURE); } The above code example is available pre-packaged as the explain_real- loc_or_die(3) function. 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. ptr The original ptr, exactly as passed to the realloc(3) system call. size The original size, exactly as passed to the realloc(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, in- cluding 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_realloc void explain_message_realloc(char *message, int message_size, void *ptr, size_t size); The explain_message_realloc function may be used to obtain an explana- tion of an error returned by the realloc(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. This function is intended to be used in a fashion similar to the fol- lowing example: void *new_ptr = realloc(ptr, size); if (!new_ptr) { char message[3000]; explain_message_realloc(message, sizeof(message), ptr, size); fprintf(stderr, "%s\n", message); exit(EXIT_FAILURE); } The above code example is available pre-packaged as the explain_real- loc_or_die(3) function. 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 re- turned message. ptr The original ptr, exactly as passed to the realloc(3) system call. size The original size, exactly as passed to the realloc(3) system call. explain_message_errno_realloc void explain_message_errno_realloc(char *message, int message_size, int errnum, void *ptr, size_t size); The explain_message_errno_realloc function may be used to obtain an ex- planation of an error returned by the realloc(3) system call. The least the message 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 fol- lowing example: void *new_ptr = realloc(ptr, size); if (!new_ptr) { int err = errno; char message[3000]; explain_message_errno_realloc(message, sizeof(message), err, ptr, size); fprintf(stderr, "%s\n", message); exit(EXIT_FAILURE); } The above code example is available pre-packaged as the explain_real- loc_or_die(3) function. 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 re- turned 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. ptr The original ptr, exactly as passed to the realloc(3) system call. size The original size, exactly as passed to the realloc(3) system call. SEE ALSO realloc(3) Allocate and free dynamic memory explain_realloc_or_die(3) Allocate and free dynamic memory and report errors COPYRIGHT libexplain version 1.3 Copyright (C) 2009 Peter Miller explain_realloc(3)
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