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C library function - fflush()
Description
The C library function int fflush(FILE *stream) flushes the output buffer of a stream.
Declaration
Following is the declaration for fflush() function.
int fflush(FILE *stream)
Parameters
stream − This is the pointer to a FILE object that specifies a buffered stream.
Return Value
This function returns a zero value on success. If an error occurs, EOF is returned and the error indicator is set (i.e. feof).
Example
The following example shows the usage of fflush() function.
#include <stdio.h> #include <string.h> int main () { char buff[1024]; memset( buff, '\0', sizeof( buff )); fprintf(stdout, "Going to set full buffering on\n"); setvbuf(stdout, buff, _IOFBF, 1024); fprintf(stdout, "This is tutorialspoint.com\n"); fprintf(stdout, "This output will go into buff\n"); fflush( stdout ); fprintf(stdout, "and this will appear when programm\n"); fprintf(stdout, "will come after sleeping 5 seconds\n"); sleep(5); return(0); }
Let us compile and run the above program that will produce the following result. Here program keeps buffering into the output into buff until it faces first call to fflush(), after which it again starts buffering the output and finally sleeps for 5 seconds. It sends remaining output to the STDOUT before program comes out.
Going to set full buffering on This is tutorialspoint.com This output will go into buff and this will appear when programm will come after sleeping 5 seconds
stdio_h.htm
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