ferror()
QNX SDP8.0C Library ReferenceAPIDeveloper
Test a stream's error flag
Synopsis:
#include <stdio.h>
int ferror( FILE* fp );
Arguments:
- fp
 - The stream whose error flag you want to test.
 
Library:
libc
Use the -l c option to qcc to link against this library. This library is usually included automatically.
Description:
The ferror() function tests the error flag for the stream specified by fp. It does not change the value of errno if the stream is valid.
Returns:
0 if the error flag isn't set, or nonzero if the error flag is set.
Examples:
#include <stdio.h>
#include <stdlib.h>
int main( void )
{
    FILE *fp;
    int c;
    fp = fopen( "file", "r" );
    if( fp != NULL ) {
        c = fgetc( fp );
        if( ferror( fp ) ) {
            printf( "Error reading file\n" );
        }
    }
    fclose( fp );
    
    return EXIT_SUCCESS;
}
Classification:
| Safety: | |
|---|---|
| Cancellation point | No | 
| Signal handler | No | 
| Thread | Yes | 
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