Provided by: libexplain-dev_1.4.D001-8_amd64 bug

NAME

       explain_execvp - explain execvp(3) errors

SYNOPSIS

       #include <libexplain/execvp.h>
       const char *explain_execvp(const char *pathname, char *const *argv);
       const char *explain_errno_execvp(int errnum, const char *pathname, char *const *argv);
       void  explain_message_execvp(char  *message,  int message_size, const char *pathname, char
       *const *argv);
       void explain_message_errno_execvp(char *message, int message_size, int errnum, const  char
       *pathname, char *const *argv);

DESCRIPTION

       These  functions  may  be used to obtain explanations for errors returned by the execvp(3)
       system call.

   explain_execvp
       const char *explain_execvp(const char *pathname, char *const *argv);

       The explain_execvp function is used to obtain an explanation of an error returned  by  the
       execvp(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 following example:
              if (execvp(pathname, argv) < 0)
              {
                  fprintf(stderr, "%s\n", explain_execvp(pathname, argv));
                  exit(EXIT_FAILURE);
              }

       The above code example is available pre‐packaged as the explain_execvp_or_die(3) function.

       pathname
               The original pathname, exactly as passed to the execvp(3) system call.

       argv    The original argv, exactly as passed to the execvp(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.

   explain_errno_execvp
       const char *explain_errno_execvp(int errnum, const char *pathname, char *const *argv);

       The explain_errno_execvp function is used to obtain an explanation of an error returned by
       the execvp(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 following example:
              if (execvp(pathname, argv) < 0)
              {
                  int err = errno;
                  fprintf(stderr, "%s\n", explain_errno_execvp(err,
                      pathname, argv));
                  exit(EXIT_FAILURE);
              }

       The above code example is available pre‐packaged as the explain_execvp_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.

       pathname
               The original pathname, exactly as passed to the execvp(3) system call.

       argv    The original argv, exactly as passed to the execvp(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.

   explain_message_execvp
       void  explain_message_execvp(char  *message,  int message_size, const char *pathname, char
       *const *argv);

       The explain_message_execvp function may be used to  obtain  an  explanation  of  an  error
       returned by the execvp(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 following example:
              if (execvp(pathname, argv) < 0)
              {
                  char message[3000];
                  explain_message_execvp(message, sizeof(message), pathname, argv);
                  fprintf(stderr, "%s\n", message);
                  exit(EXIT_FAILURE);
              }

       The above code example is available pre‐packaged as the explain_execvp_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 returned message.

       pathname
               The original pathname, exactly as passed to the execvp(3) system call.

       argv    The original argv, exactly as passed to the execvp(3) system call.

   explain_message_errno_execvp
       void explain_message_errno_execvp(char *message, int message_size, int errnum, const  char
       *pathname, char *const *argv);

       The explain_message_errno_execvp function may be used to obtain an explanation of an error
       returned by the execvp(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 following example:
              if (execvp(pathname, argv) < 0)
              {
                  int err = errno;
                  char message[3000];
                  explain_message_errno_execvp(message, sizeof(message),
                      err, pathname, argv);
                  fprintf(stderr, "%s\n", message);
                  exit(EXIT_FAILURE);
              }

       The above code example is available pre‐packaged as the explain_execvp_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 returned 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.

       pathname
               The original pathname, exactly as passed to the execvp(3) system call.

       argv    The original argv, exactly as passed to the execvp(3) system call.

SEE ALSO

       execvp(3)
               execute a file

       explain_execvp_or_die(3)
               execute a file and report errors

COPYRIGHT

       libexplain version 1.4
       Copyright (C) 2009 Peter Miller

                                                                                explain_execvp(3)