Provided by: libexplain-dev_1.4.D001-7_amd64 
NAME
explain_execv - explain execv(3) errors
SYNOPSIS
#include <libexplain/execv.h>
const char *explain_execv(const char *pathname, char *const*argv);
const char *explain_errno_execv(int errnum, const char *pathname, char *const*argv);
void explain_message_execv(char *message, int message_size, const char *pathname, char *const*argv);
void explain_message_errno_execv(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 execv(3) system call.
explain_execv
const char *explain_execv(const char *pathname, char *const*argv);
The explain_execv function is used to obtain an explanation of an error returned by the execv(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.
pathname
The original pathname, exactly as passed to the execv(3) system call.
argv The original argv, exactly as passed to the execv(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.
Example: This function is intended to be used in a fashion similar to the following example:
if (execv(pathname, argv) < 0)
{
fprintf(stderr, "%s\n", explain_execv(pathname, argv));
exit(EXIT_FAILURE);
}
The above code example is available pre-packaged as the explain_execv_or_die(3) function.
explain_errno_execv
const char *explain_errno_execv(int errnum, const char *pathname, char *const*argv);
The explain_errno_execv function is used to obtain an explanation of an error returned by the execv(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.
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 execv(3) system call.
argv The original argv, exactly as passed to the execv(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.
Example: This function is intended to be used in a fashion similar to the following example:
if (execv(pathname, argv) < 0)
{
int err = errno;
fprintf(stderr, "%s\n", explain_errno_execv(err, pathname, argv));
exit(EXIT_FAILURE);
}
The above code example is available pre-packaged as the explain_execv_or_die(3) function.
explain_message_execv
void explain_message_execv(char *message, int message_size, const char *pathname, char *const*argv);
The explain_message_execv function is used to obtain an explanation of an error returned by the execv(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.
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 execv(3) system call.
argv The original argv, exactly as passed to the execv(3) system call.
Example: This function is intended to be used in a fashion similar to the following example:
if (execv(pathname, argv) < 0)
{
char message[3000];
explain_message_execv(message, sizeof(message), pathname, argv);
fprintf(stderr, "%s\n", message);
exit(EXIT_FAILURE);
}
The above code example is available pre-packaged as the explain_execv_or_die(3) function.
explain_message_errno_execv
void explain_message_errno_execv(char *message, int message_size, int errnum, const char *pathname, char
*const*argv);
The explain_message_errno_execv function is used to obtain an explanation of an error returned by the
execv(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.
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 execv(3) system call.
argv The original argv, exactly as passed to the execv(3) system call.
Example: This function is intended to be used in a fashion similar to the following example:
if (execv(pathname, argv) < 0)
{
int err = errno;
char message[3000];
explain_message_errno_execv(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_execv_or_die(3) function.
SEE ALSO
execv(3)
execute a file
explain_execv_or_die(3)
execute a file and report errors
COPYRIGHT
libexplain version 1.4
Copyright (C) 2012 Peter Miller
explain_execv(3)