explain_getpriority(3) Library Functions Manual explain_getpriority(3) NAME explain_getpriority - explain getpriority(2) errors SYNOPSIS #include <libexplain/getpriority.h> const char *explain_getpriority(int which, int who); const char *explain_errno_getpriority(int errnum, int which, int who); void explain_message_getpriority(char *message, int message_size, int which, int who); void explain_message_errno_getpriority(char *message, int message_size, int errnum, int which, int who); DESCRIPTION These functions may be used to obtain explanations for errors returned by the getpriority(2) system call. explain_getpriority const char *explain_getpriority(int which, int who); The explain_getpriority function is used to obtain an explanation of an er- ror returned by the getpriority(2) 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. which The original which, exactly as passed to the getpriority(2) system call. who The original who, exactly as passed to the getpriority(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 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. Example: This function is intended to be used in a fashion similar to the following example: int result = getpriority(which, who); if (result < 0) { fprintf(stderr, "%s\n", explain_getpriority(which, who)); exit(EXIT_FAILURE); } The above code example is available pre-packaged as the explain_getprior- ity_or_die(3) function. explain_errno_getpriority const char *explain_errno_getpriority(int errnum, int which, int who); The explain_errno_getpriority function is used to obtain an explanation of an error returned by the getpriority(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. 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 ex- plained and this function, because many libc functions will alter the value of errno. which The original which, exactly as passed to the getpriority(2) system call. who The original who, exactly as passed to the getpriority(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 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. Example: This function is intended to be used in a fashion similar to the following example: int result = getpriority(which, who); if (result < 0) { int err = errno; fprintf(stderr, "%s\n", explain_errno_getpriority(err, which, who)); exit(EXIT_FAILURE); } The above code example is available pre-packaged as the explain_getprior- ity_or_die(3) function. explain_message_getpriority void explain_message_getpriority(char *message, int message_size, int which, int who); The explain_message_getpriority function is used to obtain an explanation of an error returned by the getpriority(2) 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 de- coded. 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. which The original which, exactly as passed to the getpriority(2) system call. who The original who, exactly as passed to the getpriority(2) system call. Example: This function is intended to be used in a fashion similar to the following example: int result = getpriority(which, who); if (result < 0) { char message[3000]; explain_message_getpriority(message, sizeof(message), which, who); fprintf(stderr, "%s\n", message); exit(EXIT_FAILURE); } The above code example is available pre-packaged as the explain_getprior- ity_or_die(3) function. explain_message_errno_getpriority void explain_message_errno_getpriority(char *message, int message_size, int errnum, int which, int who); The explain_message_errno_getpriority function is used to obtain an expla- nation of an error returned by the getpriority(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. 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 ex- plained and this function, because many libc functions will alter the value of errno. which The original which, exactly as passed to the getpriority(2) system call. who The original who, exactly as passed to the getpriority(2) system call. Example: This function is intended to be used in a fashion similar to the following example: int result = getpriority(which, who); if (result < 0) { int err = errno; char message[3000]; explain_message_errno_getpriority(message, sizeof(message), err, which, who); fprintf(stderr, "%s\n", message); exit(EXIT_FAILURE); } The above code example is available pre-packaged as the explain_getprior- ity_or_die(3) function. SEE ALSO getpriority(2) get program scheduling priority explain_getpriority_or_die(3) get program scheduling priority and report errors COPYRIGHT libexplain version 1.3 Copyright (C) 2013 Peter Miller explain_getpriority(3)
NAME | SYNOPSIS | DESCRIPTION | SEE ALSO | COPYRIGHT
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