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_makepath_s, _wmakepath_s

Creates a path name from components. These are versions of _makepath, _wmakepath with security enhancements as described in Security Features in the CRT.

errno_t _makepath_s(
   char *path,
   size_t sizeInBytes,
   const char *drive,
   const char *dir,
   const char *fname,
   const char *ext 
);
errno_t _wmakepath_s(
   wchar_t *path,
   size_t sizeInWords,
   const wchar_t *drive,
   const wchar_t *dir,
   const wchar_t *fname,
   const wchar_t *ext 
);
template <size_t size>
errno_t _makepath_s(
   char (&path)[size],
   const char *drive,
   const char *dir,
   const char *fname,
   const char *ext 
); // C++ only
template <size_t size>
errno_t _wmakepath_s(
   wchar_t (&path)[size],
   const wchar_t *drive,
   const wchar_t *dir,
   const wchar_t *fname,
   const wchar_t *ext 
); // C++ only

[out] path

Full path buffer.

[in] sizeInWords

Size of the buffer in words.

[in] sizeInBytes

Size of the buffer in bytes.

[in] drive

Contains a letter (A, B, and so on) corresponding to the desired drive and an optional trailing colon. _makepath_s inserts the colon automatically in the composite path if it is missing. If drive is NULL or points to an empty string, no drive letter appears in the composite path string.

[in] dir

Contains the path of directories, not including the drive designator or the actual file name. The trailing slash is optional, and either a forward slash (/) or a backslash (\) or both might be used in a single dir argument. If no trailing slash (/ or \) is specified, it is inserted automatically. If dir is NULL or points to an empty string, no directory path is inserted in the composite path string.

[in] fname

Contains the base file name without any file name extensions. If fname is NULL or points to an empty string, no filename is inserted in the composite path string.

[in] ext

Contains the actual file name extension, with or without a leading period (.). _makepath_s inserts the period automatically if it does not appear in ext. If ext is NULL or points to an empty string, no extension is inserted in the composite path string.

Zero if successful; an error code on failure.

Error Conditions

path

sizeInWords / sizeInBytes

Return

Contents of path

NULL

any

EINVAL

not modified

any

<= 0

EINVAL

not modified

If any of the above error conditions occurs, these functions invoke the invalid parameter handler, as described in Parameter Validation. If execution is allowed to continue, errno is set toEINVAL and the functions returnsEINVAL. NULL is allowed for the parameters drive, fname, and ext. For information about the behavior when these parameters are null pointers or empty strings, see the Remarks section.

The _makepath_s function creates a composite path string from individual components, storing the result in path. The path might include a drive letter, directory path, file name, and file name extension. _wmakepath_s is a wide-character version of _makepath_s; the arguments to _wmakepath_s are wide-character strings. _wmakepath_s and _makepath_s behave identically otherwise.

Generic-Text Routine Mappings

Tchar.h routine

_UNICODE and _MBCS not defined

_MBCS defined

_UNICODE defined

_tmakepath_s

_makepath_s

_makepath_s

_wmakepath_s

The path argument must point to an empty buffer large enough to hold the complete path. The composite path must be no larger than the _MAX_PATH constant, defined in Stdlib.h.

If path is NULL, the invalid parameter handler is invoked, as described in Parameter Validation. In addition, errno is set to EINVAL. NULL values are allowed for all other parameters.

In C++, using these functions is simplified by template overloads; the overloads can infer buffer length automatically (eliminating the need to specify a size argument) and they can automatically replace older, non-secure functions with their newer, secure counterparts. For more information, see Secure Template Overloads.

The debug versions of these functions first fill the buffer with 0xFD. To disable this behavior, use _CrtSetDebugFillThreshold.

Routine

Required header

_makepath_s

<stdlib.h>

_wmakepath_s

<stdlib.h> or <wchar.h>

For more compatibility information, see Compatibility in the Introduction.

// crt_makepath_s.c

#include <stdlib.h>
#include <stdio.h>

int main( void )
{
   char path_buffer[_MAX_PATH];
   char drive[_MAX_DRIVE];
   char dir[_MAX_DIR];
   char fname[_MAX_FNAME];
   char ext[_MAX_EXT];
   errno_t err;

   err = _makepath_s( path_buffer, _MAX_PATH, "c", "\\sample\\crt\\",
                      "crt_makepath_s", "c" );
   if (err != 0)
   {
      printf("Error creating path. Error code %d.\n", err);
      exit(1);
   }
   printf( "Path created with _makepath_s: %s\n\n", path_buffer );
   err = _splitpath_s( path_buffer, drive, _MAX_DRIVE, dir, _MAX_DIR, fname,
                       _MAX_FNAME, ext, _MAX_EXT );
   if (err != 0)
   {
      printf("Error splitting the path. Error code %d.\n", err);
      exit(1);
   }
   printf( "Path extracted with _splitpath_s:\n" );
   printf( "  Drive: %s\n", drive );
   printf( "  Dir: %s\n", dir );
   printf( "  Filename: %s\n", fname );
   printf( "  Ext: %s\n", ext );
}

Path created with _makepath_s: c:\sample\crt\crt_makepath_s.c

Path extracted with _splitpath_s:
  Drive: c:
  Dir: \sample\crt\
  Filename: crt_makepath_s
  Ext: .c

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