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ferror()                   STDIO Macro                   ferror()




Discover stream status

#include <stdio.h>
iinntt ffeerrrroorr(_f_p) FFIILLEE *_f_p;

ferror is  a macro that tests  the status of the  file stream fp.
It returns a  number other than zero if an  error has occurred on
fp.  Any  error condition that is  discovered will persist either
until the stream is closed or until clearerr is used to clear it.
For write  routines that employ buffers,  fflush should be called
before ferror, in case an error occurs on the last block written.

***** Example *****

This  example reads  a  word from  one  file and  writes it  into
another.


#include <stdio.h>



main()
{
        FILE *fpin, *fpout;
        int inerr = 0;
        int outerr = 0;
        int word;
        char infile[20], outfile[20];



        printf("Name data file you wish to copy:\n");
        gets(infile);
        printf("Name new file:\n");
        gets(outfile);



        if ((fpin = fopen(infile, "r")) != NULL) {
                if ((fpout = fopen(outfile, "w")) != NULL) {



                        for (;;) {
                                word = fgetw(fpin);
                                if (ferror(fpin)) {
                                        clearerr(fpin);
                                        inerr++;
                                }






COHERENT Lexicon                                           Page 1




ferror()                   STDIO Macro                   ferror()



                                if (feof(fpin))
                                        break;
                                fputw(word, fpout);
                                if (ferror(fpout)) {
                                        clearerr(fpout);
                                        outerr++;
                                }
                        }



                } else {
                        printf
                                ("Cannot open output file %s\n",
                                        outfile);
                        exit(1);
                }



        } else {
                printf("Cannot open input file %s\n", infile);
                exit(1);
        }



        printf("%d - read error(s)  %d - write error(s)\n",
                inerr, outerr);
        exit(0);
}


***** See Also *****

STDIO





















COHERENT Lexicon                                           Page 2

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