fmemopen, open_memstream, open_wmemstream

NAME 

 fmemopen, open_memstream, open_wmemstream -  open memory as stream

SYNOPSIS        

       #include <stdio.h>



       FILE *fmemopen(void *buf, size_t size, const char *mode);



       FILE *open_memstream(char **ptr, size_t *sizeloc);



       #include <wchar.h>



       FILE *open_wmemstream(wchar_t **ptr, size_t *sizeloc);



       fmemopen(), open_memstream(), open_wmemstream():

           Since glibc 2.10:

               _XOPEN_SOURCE >= 700 || _POSIX_C_SOURCE >= 200809L

           Before glibc 2.10:

               _GNU_SOURCE

 RETURN VALUE         
       Upon successful completion fmemopen(), open_memstream() and open_wmemstream()

       return a FILE pointer.  Otherwise, NULL is returned and errno is set to

       indicate the error.



VERSIONS        

       fmemopen() and open_memstream() were already available in glibc 1.0.x.

       open_wmemstream() is available since glibc 2.4.



Program source
       #define _GNU_SOURCE

       #include <string.h>

       #include <stdio.h>

       #include <stdlib.h>



       #define handle_error(msg) /

           do { perror(msg); exit(EXIT_FAILURE); } while (0)



       int

       main(int argc, char *argv[])

       {

           FILE *out, *in;

           int v, s;

           size_t size;

           char *ptr;



           if (argc != 2) {

            fprintf(stderr, "Usage: %s <file>/n", argv[0]);

            exit(EXIT_FAILURE);

           }



           in = fmemopen(argv[1], strlen(argv[1]), "r");

           if (in == NULL)

               handle_error("fmemopen");



           out = open_memstream(&ptr, &size);

           if (out == NULL)

               handle_error("open_memstream");



           for (;;) {

               s = fscanf(in, "%d", &v);

               if (s <= 0)

                   break;



               s = fprintf(out, "%d ", v * v);

               if (s == -1)

                   handle_error("fprintf");

           }

           fclose(in);

           fclose(out);

           printf("size=%ld; ptr=%s/n", (long) size, ptr);

           free(ptr);

           exit(EXIT_SUCCESS);

       }



 Ref: http://www.kernel.org/doc/man-pages/online/pages/man3/fmemopen.3.html

 Home: http://www.kernel.org/doc/man-pages/index.html