_getc_nolock, _getwc_nolock

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06/05/2017

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The latest version of this topic can be found at _getc_nolock, _getwc_nolock.

Reads a character from a stream.

Syntax

int _getc_nolock(   
   FILE *stream   
);  
wint_t _getwc_nolock(   
   FILE *stream   
);

Parameters

stream
Input stream.

Return Value

See getc, getwc.

Remarks

These functions are identical to getc and getwc except that they do not lock the calling thread. They might be faster because they do not incur the overhead of locking out other threads. Use these functions only in thread-safe contexts such as single-threaded applications or where the calling scope already handles thread isolation.

Generic-Text Routine Mappings

Tchar.h routine	_UNICODE and _MBCS not defined	_MBCS defined	_UNICODE defined
`_gettc_nolock`	`getc_nolock`	`getc_nolock`	`getwc_nolock`

Requirements

Routine	Required header
`getc_nolock`	<stdio.h>
`getwc_nolock`	<stdio.h> or <wchar.h>

For more compatibility information, see Compatibility in the Introduction.

Example

// crt_getc_nolock.c  
// Use getc to read a line from a file.  
  
#include <stdio.h>  
  
int main()  
{  
    char buffer[81];  
    int i, ch;  
    FILE* fp;  
  
    // Read a single line from the file "crt_getc_nolock.txt".  
    fopen_s(&fp, "crt_getc_nolock.txt", "r");  
    if (!fp)  
    {  
       printf("Failed to open file crt_getc_nolock.txt.\n");  
       exit(1);  
    }  
  
    for (i = 0; (i < 80) && ((ch = getc(fp)) != EOF)  
                         && (ch != '\n'); i++)  
    {  
        buffer[i] = (char) ch;  
    }  
  
    // Terminate string with a null character   
    buffer[i] = '\0';  
    printf( "Input was: %s\n", buffer);  
  
    fclose(fp);  
}

Input: crt_getc_nolock.txt

Line the first.  
Line the second.

Output

Input was: Line the first.

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