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explain_wait(3) Library Functions Manual explain_wait(3) NAME explain_wait - explain wait(2) errors SYNOPSIS #include <libexplain/wait.h> const char *explain_wait(int *status); const char *explain_errno_wait(int errnum, int *status); void explain_message_wait(char *message, int message_size, int *sta- tus); void explain_message_errno_wait(char *message, int message_size, int errnum, int *status); DESCRIPTION These functions may be used to obtain explanations for errors returned by the wait(2) system call. explain_wait const char *explain_wait(int *status); The explain_wait function is used to obtain an explanation of an error returned by the wait(2) system call. The least the message will con- tain 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 decoded. This function is intended to be used in a fashion similar to the fol- lowing example: if (wait(status) < 0) { fprintf(stderr, "%s\n", explain_wait(status)); exit(EXIT_FAILURE); } status The original status, exactly as passed to the wait(2) 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_wait const char *explain_errno_wait(int errnum, int *status); The explain_errno_wait function is used to obtain an explanation of an error returned by the wait(2) 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: if (wait(status) < 0) { int err = errno; fprintf(stderr, "%s\n", explain_errno_wait(err, status)); 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 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. status The original status, exactly as passed to the wait(2) 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_wait void explain_message_wait(char *message, int message_size, int *sta- tus); The explain_message_wait function may be used to obtain an explanation of an error returned by the wait(2) 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: if (wait(status) < 0) { char message[3000]; explain_message_wait(message, sizeof(message), status); 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 re- turned message. status The original status, exactly as passed to the wait(2) system call. explain_message_errno_wait void explain_message_errno_wait(char *message, int message_size, int errnum, int *status); The explain_message_errno_wait function may be used to obtain an expla- nation of an error returned by the wait(2) 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: if (wait(status) < 0) { int err = errno; char message[3000]; explain_message_errno_wait(message, sizeof(message), err, status); 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 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. status The original status, exactly as passed to the wait(2) system call. SEE ALSO wait(2) wait for process to change state explain_wait_or_die(3) wait for process to change state and report errors COPYRIGHT libexplain version 1.3 Copyright (C) 2008 Peter Miller explain_wait(3)
NAME | SYNOPSIS | DESCRIPTION | SEE ALSO | COPYRIGHT
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