fgets, fgetws

Articolo
06/05/2017

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Get a string from a stream.

Syntax

char *fgets(   
   char *str,  
   int n,  
   FILE *stream   
);  
wchar_t *fgetws(   
   wchar_t *str,  
   int n,  
   FILE *stream   
);

Parameters

str
Storage location for data.

n
Maximum number of characters to read.

stream
Pointer to FILE structure.

Return Value

Each of these functions returns str. NULL is returned to indicate an error or an end-of-file condition. Use feof or ferror to determine whether an error occurred. If str or stream is a null pointer, or n is less than or equal to zero, this function invokes the invalid parameter handler, as described in Parameter Validation. If execution is allowed to continue, errno is set to EINVAL and the function returns NULL.

See _doserrno, errno, _sys_errlist, and _sys_nerr for more information on these, and other, error codes.

Remarks

The fgets function reads a string from the input stream argument and stores it in str. fgets reads characters from the current stream position to and including the first newline character, to the end of the stream, or until the number of characters read is equal to n – 1, whichever comes first. The result stored in str is appended with a null character. The newline character, if read, is included in the string.

fgetws is a wide-character version of fgets.

fgetws reads the wide-character argument str as a multibyte-character string or a wide-character string according to whether stream is opened in text mode or binary mode, respectively. For more information about using text and binary modes in Unicode and multibyte stream-I/O, see Text and Binary Mode File I/O and Unicode Stream I/O in Text and Binary Modes.

Generic-Text Routine Mappings

TCHAR.H routine	_UNICODE & _MBCS not defined	_MBCS defined	_UNICODE defined
`_fgetts`	`fgets`	`fgets`	`fgetws`

Requirements

Function	Required header
`fgets`	<stdio.h>
`fgetws`	<stdio.h> or <wchar.h>

For additional compatibility information, see Compatibility in the Introduction.

Example

// crt_fgets.c  
// This program uses fgets to display  
// a line from a file on the screen.  
//  
  
#include <stdio.h>  
  
int main( void )  
{  
   FILE *stream;  
   char line[100];  
  
   if( fopen_s( &stream, "crt_fgets.txt", "r" ) == 0 )  
   {  
      if( fgets( line, 100, stream ) == NULL)  
         printf( "fgets error\n" );  
      else  
         printf( "%s", line);  
      fclose( stream );  
   }  
}

Input: crt_fgets.txt

Line one.  
Line two.

Output

Line one.

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