对于标题“fcntl.h”中的这个错误，我应该修改什么？

Question

I was doing image processing using opencv.. but then this error comes out when i debug the main program. I dont what need to be modify from this header file since im not quite familiar when it comes to error in the header file.

/*
 *      POSIX Standard: 6.5 File Control Operations     <fcntl.h>
 */

#ifndef _FCNTL_H
#define _FCNTL_H        1

#include <features.h>

/* This must be early so <bits/fcntl.h> can define types winningly.  */
__BEGIN_DECLS

/* Get the definitions of O_*, F_*, FD_*: all the
   numbers and flag bits for `open', `fcntl', et al.  */
#include <bits/fcntl.h>

/* For XPG all symbols from <sys/stat.h> should also be available.  */
#ifdef __USE_XOPEN
# include <sys/stat.h>
#endif

#ifdef  __USE_MISC
# ifndef R_OK                   /* Verbatim from <unistd.h>.  Ugh.  */
/* Values for the second argument to access.
   These may be OR'd together.  */
#  define R_OK  4               /* Test for read permission.  */
#  define W_OK  2               /* Test for write permission.  */
#  define X_OK  1               /* Test for execute permission.  */
#  define F_OK  0               /* Test for existence.  */
# endif
#endif /* Use misc.  */

/* XPG wants the following symbols.  */
#ifdef __USE_XOPEN              /* <stdio.h> has the same definitions.  */
# define SEEK_SET       0       /* Seek from beginning of file.  */
# define SEEK_CUR       1       /* Seek from current position.  */
# define SEEK_END       2       /* Seek from end of file.  */
#endif  /* XPG */

/* Do the file control operation described by CMD on FD.
   The remaining arguments are interpreted depending on CMD.

   This function is a cancellation point and therefore not marked with
   __THROW.  */
extern int fcntl (int __fd, int __cmd, ...);

/* Open FILE and return a new file descriptor for it, or -1 on error.
   OFLAG determines the type of access used.  If O_CREAT is on OFLAG,
   the third argument is taken as a `mode_t', the mode of the created file.

   This function is a cancellation point and therefore not marked with
   __THROW.  */
#ifndef __USE_FILE_OFFSET64
extern int open (__const char *__file, int __oflag, ...) __nonnull ((1));
#else
# ifdef __REDIRECT
extern int __REDIRECT (open, (__const char *__file, int __oflag, ...), open64)
     __nonnull ((1));
# else
#  define open open64
# endif
#endif
#ifdef __USE_LARGEFILE64
extern int open64 (__const char *__file, int __oflag, ...) __nonnull ((1));
#endif

#ifdef __USE_ATFILE
/* Similar to `open' but a relative path name is interpreted relative to
   the directory for which FD is a descriptor.

   NOTE: some other `openat' implementation support additional functionality
   through this interface, especially using the O_XATTR flag.  This is not
   yet supported here.

   This function is a cancellation point and therefore not marked with
   __THROW.  */
# ifndef __USE_FILE_OFFSET64
extern int openat (int __fd, __const char *__file, int __oflag, ...)
     __nonnull ((2));
# else
#  ifdef __REDIRECT
extern int __REDIRECT (openat, (int __fd, __const char *__file, int __oflag,
                                ...), openat64) __nonnull ((2));
#  else
#   define openat openat64
#  endif
# endif

extern int openat64 (int __fd, __const char *__file, int __oflag, ...)
     __nonnull ((2));
#endif

/* Create and open FILE, with mode MODE.  This takes an `int' MODE
   argument because that is what `mode_t' will be widened to.

   This function is a cancellation point and therefore not marked with
   __THROW.  */
#ifndef __USE_FILE_OFFSET64
extern int creat (__const char *__file, __mode_t __mode) __nonnull ((1));
#else
# ifdef __REDIRECT
extern int __REDIRECT (creat, (__const char *__file, __mode_t __mode),
                       creat64) __nonnull ((1));
# else
#  define creat creat64
# endif
#endif
#ifdef __USE_LARGEFILE64
extern int creat64 (__const char *__file, __mode_t __mode) __nonnull ((1));
#endif

#if !defined F_LOCK && (defined __USE_MISC || (defined __USE_XOPEN_EXTENDED \
                                               && !defined __USE_POSIX))
/* NOTE: These declarations also appear in <unistd.h>; be sure to keep both
   files consistent.  Some systems have them there and some here, and some
   software depends on the macros being defined without including both.  */

/* `lockf' is a simpler interface to the locking facilities of `fcntl'.
   LEN is always relative to the current file position.
   The CMD argument is one of the following.  */

# define F_ULOCK 0      /* Unlock a previously locked region.  */
# define F_LOCK  1      /* Lock a region for exclusive use.  */
# define F_TLOCK 2      /* Test and lock a region for exclusive use.  */
# define F_TEST  3      /* Test a region for other processes locks.  */

# ifndef __USE_FILE_OFFSET64
extern int lockf (int __fd, int __cmd, __off_t __len);
# else
#  ifdef __REDIRECT
extern int __REDIRECT (lockf, (int __fd, int __cmd, __off64_t __len), lockf64);
#  else
#   define lockf lockf64
#  endif
# endif
# ifdef __USE_LARGEFILE64
extern int lockf64 (int __fd, int __cmd, __off64_t __len);
# endif
#endif

#ifdef __USE_XOPEN2K
/* Advice the system about the expected behaviour of the application with
   respect to the file associated with FD.  */
# ifndef __USE_FILE_OFFSET64
extern int posix_fadvise (int __fd, __off_t __offset, __off_t __len,
                          int __advise) __THROW;
# else
 # ifdef __REDIRECT_NTH
extern int __REDIRECT_NTH (posix_fadvise, (int __fd, __off64_t __offset,
                                           __off64_t __len, int __advise),
                           posix_fadvise64);
#  else
#   define posix_fadvise posix_fadvise64
#  endif
# endif
# ifdef __USE_LARGEFILE64
extern int posix_fadvise64 (int __fd, __off64_t __offset, __off64_t __len,
                            int __advise) __THROW;
# endif


/* Reserve storage for the data of the file associated with FD.

   This function is a possible cancellation points and therefore not
   marked with __THROW.  */
# ifndef __USE_FILE_OFFSET64
extern int posix_fallocate (int __fd, __off_t __offset, __off_t __len);
# else
 # ifdef __REDIRECT
extern int __REDIRECT (posix_fallocate, (int __fd, __off64_t __offset,
                                         __off64_t __len),
                       posix_fallocate64);
#  else
#   define posix_fallocate posix_fallocate64
#  endif
# endif
# ifdef __USE_LARGEFILE64
extern int posix_fallocate64 (int __fd, __off64_t __offset, __off64_t __len);
# endif
#endif


/* Define some inlines helping to catch common problems.  */
#if __USE_FORTIFY_LEVEL > 0 && defined __extern_always_inline \
    && defined __va_arg_pack_len
# include <bits/fcntl2.h>
#endif

__END_DECLS

#endif /* fcntl.h  */

It shows this kind of error.

/usr/include/fcntl.h||In function ‘int main(int, char**)’:|
/usr/include/fcntl.h|73|error: too few arguments to function ‘int
open(const char*, int, ...)’|

Answer 1

What should I modify for this error in the header “fcntl.h”?

Don't / Never modify anything in the fcntl.h . Go the source code main function and provide the second (command) argument (and if needed more arguments) to open .

The original problem lies in your main function (File name would be available in full error log).